or [ər, 'ȯr, Southern also 'är] -conj

  1. used as a function word to indicate an alternative
    • coffee or tea
    • sink or swim
    , the equivalent or substitutive character of two words or phrases
    • lessen or abate
    , or approximation or uncertainty
    • in five or six days
  2. either
  3. whether
  4. used in logic as a sentential connective that forms a complex sentence which is true when at least one of its constituent sentences is true
  5. before
  6. before
  7. the heraldic color gold or yellow

OR ['ȯr] -n

  1. a logical operator that requires either of two inputs to be present or conditions to be met for an output to be made or a statement to be executed
    • OR gate in a computer
  2. operating room
  3. operational research; operations research
  4. Oregon
  5. owner's risk
  6. own recognizance

ora ['äs] -n

(variant of os)

  1. bone
  2. orifice

or·ache ['ȯr-ich, 'är-] -n

  1. any of various herbs (genus Atriplex) of the goosefoot family that include some (as A. hortensis) with edible leaves

or·a·cle ['ȯr-ə-kəl, 'är-] -n

  1. a person (as a priestess of ancient Greece) through whom a deity is believed to speak
  2. a shrine in which a deity reveals hidden knowledge or the divine purpose through such a person
  3. an answer or decision given by an oracle
  4. a person giving wise or authoritative decisions or opinions
  5. an authoritative or wise expression or answer

orac·u·lar [ȯ-'ra-kyə-lər, ə-] -adj, n, adv

  1. resembling an oracle (as in solemnity of delivery)
  2. of, relating to, or being an oracle

oral ['ȯr-əl, 'är-] -adj, n, adv

  1. uttered by the mouth or in words : spoken
    • oral traditions
  2. using speech or the lips esp. in teaching the deaf
  3. of, given through, or involving the mouth
    • oral health
    • an oral vaccine
  4. being on or relating to the same surface as the mouth
  5. of, relating to, or characterized by the first stage of psychosexual development in psychoanalytic theory during which libidinal gratification is derived from intake (as of food), by sucking, and later by biting
  6. of, relating to, or characterized by personality traits of passive dependency and aggressiveness
  7. an oral examination usu. used in pl.

oral contraceptive -n

  1. birth control pill

oral history -n

  1. tape-recorded historical information obtained in interviews concerning personal experiences and recollections
  2. the study of such information
  3. a written work based on oral history

oral·ism ['ȯr-ə-,li-zəm, 'är-] -n

  1. advocacy or use of the oral method of teaching the deaf

oral sex -n

  1. oral stimulation of the genitals : cunnilingus, fellatio

orang [ə-'raŋ] -n

  1. orangutan

or·ange ['är-inj, 'är(-ə)nj; chiefly Northern & Midland 'ȯr-inj, 'ȯr(-ə)nj] -n

  1. a globose berry with a yellowish to reddish-orange rind and a sweet edible pulp
  2. any of various small evergreen citrus trees (genus Citrus) with glossy ovate leaves, hard yellow wood, fragrant white flowers, and fruits that are oranges
  3. any of several trees or fruits resembling the orange
  4. any of a group of colors that lie midway between red and yellow in hue

orange -adj

  1. of or relating to the orange
  2. of the color orange

Orange ['är-in-,ji-zəm, 'är(ə-)n-, 'ȯr-in-, 'ȯr(ə-)n-] -adj, n

  1. of, relating to, or sympathizing with Orangemen

or·ange·ade [,är-in-'jād, ,är(-ə)n-, ,ȯr-in-, ,ȯr(-ə)n-] -n

  1. a beverage of sweetened orange juice mixed with water

orange chromide -n

  1. an Asian freshwater cichlid fish ( Etroplus maculatus) that is orange or yellow with red spots and is often kept in tropical aquariums

orange hawkweed -n

  1. a European hawkweed ( Hieracium aurantiacum) that has flower heads with bright orange-red rays and is a troublesome weed esp. in northeastern No. America

Or·ange·man ['är-inj-mən, 'är(-ə)nj-, 'ȯr-inj-, 'ȯr(-ə)nj-] -n

  1. a member of a secret society organized in the north of Ireland in 1795 to defend the British sovereign and to support the Protestant religion
  2. a Protestant Irishman esp. of Ulster

orange peel -n

  1. a rough surface (as on porcelain) like that of an orange

orange pekoe -n

  1. tea made from the smallest and youngest leaves of the shoot

orange roughy [-'rə-fē] -n

  1. a reddish-orange fish ( Hoplostethus atlanticus) of deep subtropical and tropical waters that has firm white flesh and is caught commercially chiefly in the waters of New Zealand

or·ange·ry ['är-inj-rē, 'är(-ə)nj-, 'ȯr-inj-, 'ȯr(-ə)nj-] -n

  1. a protected place and esp. a greenhouse for growing oranges in cool climates

or·ange·wood ['är-inj-,wu̇d, 'är(-ə)nj-, 'ȯr-inj-, 'ȯr(-ə)nj-] -n

  1. the wood of the orange tree used esp. in turnery and carving

or·ang·ey ['är-in-jē, 'är(-ə)n-, 'ȯr-in-, 'ȯr(-ə)n-] -adj

  1. resembling or suggestive of an orange (as in flavor or color)

or·ang·ish ['är-in-jish, 'är(-ə)n-, 'ȯr-in-, 'ȯr(-ə)n-] -adj

  1. somewhat orange

orang·u·tan [ə-'raŋ-ə-,taŋ, -'raŋ-gə-, -,tan] -n

  1. a largely herbivorous arboreal anthropoid ape ( Pongo pygmaeus) of Borneo and Sumatra that is about as large as the gorilla and has brown skin, long sparse reddish-brown hair, and very long arms

orate [ȯ-'rāt, 'ȯr-,āt] -vi

  1. to speak in an elevated and often pompous manner

ora·tion [ə-'rā-shən, ȯ-] -n

  1. an elaborate discourse delivered in a formal and dignified manner

or·a·tor ['ȯr-ə-tər, 'är-] -n

  1. one who delivers an oration
  2. one distinguished for skill and power as a public speaker

Or·a·to·ri·an [,ȯr-ə-'tȯr-ē-ən, ,är-] -n, adj

  1. a member of the Congregation of the Oratory of St. Philip Neri founded in Rome in 1575 and comprising independent communities of secular priests under obedience but without vows

or·a·tor·i·cal [,ȯr-ə-'tȯr-i-kəl, ,är-ə-'tär-] -adj, adv

  1. of, relating to, or characteristic of an orator or oratory

or·a·to·rio [,ȯr-ə-'tȯr-ē-,ō, ,är-] -n

  1. a lengthy choral work usu. of a religious nature consisting chiefly of recitatives, arias, and choruses without action or scenery

or·a·to·ry ['ȯr-ə-,tȯr-ē, 'är-] -n

  1. a place of prayer
  2. a private or institutional chapel
  3. an Oratorian congregation, house, or church

oratory -n

  1. the art of speaking in public eloquently or effectively
  2. public speaking that employs oratory
  3. public speaking that is characterized by the use of stock phrases and that appeals chiefly to the emotions

orb ['ȯrb] -n

  1. any of the concentric spheres in old astronomy surrounding the earth and carrying the celestial bodies in their revolutions
  2. something circular : circle, orbit
  3. a spherical body
  4. a spherical celestial object
  5. eye
  6. a sphere surmounted by a cross symbolizing kingly power and justice
  7. to form into a disk or circle
  8. encircle, surround, enclose
  9. to move in an orbit

or·bic·u·lar [ȯr-'bi-kyə-lər] -adj, adv

  1. spherical, circular

or·bic·u·late [ȯr-'bi-kyə-lət] -adj

  1. circular or nearly circular in outline
    • an orbiculate leaf

or·bit ['ȯr-bət] -n, adj

  1. the bony socket of the eye

orbit -n, adj

  1. a path described by one body in its revolution about another (as by the earth about the sun or by an electron about an atomic nucleus)
  2. one complete revolution of a body describing such a path
  3. a circular path
  4. a range or sphere of activity or influence
    • within the president's orbit
  5. to revolve in an orbit around : circle
  6. to send up and make revolve in an orbit
    • orbit a satellite
  7. to travel in circles

orbital -n

  1. a mathematically described region around a nucleus in an atom or molecule that may contain zero, one, or two electrons

or·bit·er [-bə-tər] -n

  1. : one that orbits: as
  2. a spacecraft designed to orbit a celestial body without landing on its surface
  3. space shuttle

orb weaver -n

  1. any of a family (Araneidae) of spiders that have eight similar eyes and typically spin a large elaborate wheel-shaped flat web

orb web -n

  1. a web made by an orb weaver

or·ca ['ȯr-kə] -n

  1. killer whale

Or·ca·di·an [ȯr-'kā-dē-ən] -n, adj

  1. a native or inhabitant of the Orkney Islands

or·chard ['ȯr-chərd] -n

  1. a planting of fruit trees, nut trees, or sugar maples
  2. the trees of such a planting

orchard grass -n

  1. a widely grown tall stout hay and pasture grass ( Dactylis glomerata) of Eurasia that grows in tufts and has loose open panicles called also cocksfoot

or·chard·ist ['ȯr-chər-dist] -n

  1. an owner or supervisor of orchards

or·ches·tra ['ȯr-kəs-trə, -,kes-] -n

  1. the circular space used by the chorus in front of the proscenium in an ancient Greek theater
  2. a corresponding semicircular space in a Roman theater used for seating important persons
  3. the space in front of the stage in a modern theater that is used by an orchestra
  4. the forward section of seats on the main floor of a theater
  5. the main floor of a theater
  6. a group of musicians including esp. string players organized to perform ensemble music

or·ches·tral [ȯr-'kes-trəl] -adj, adv

  1. of, relating to, or composed for an orchestra
  2. suggestive of an orchestra or its musical qualities

or·ches·trate ['ȯr-kə-,strāt] -vt, n

  1. to compose or arrange (music) for an orchestra
  2. to provide with orchestration
    • orchestrate a ballet
  3. to arrange or combine so as to achieve a desired or maximum effect
    • orchestrated preparations for the banquet

or·ches·tra·tion [,ȯr-kə-'strā-shən] -n, adj

  1. the arrangement of a musical composition for performance by an orchestra
  2. orchestral treatment of a musical composition
  3. harmonious organization
    • develop a world community through orchestration of cultural diversities -- L. K. Frank

or·chid ['ȯr-kəd] -n, adj

  1. any of a large family (Orchidaceae, the orchid family) of perennial epiphytic or terrestrial monocotyledonous plants that usu. have showy 3-petaled flowers with the middle petal enlarged into a lip and differing from the others in shape and color
  2. a light purple

or·chi·da·ceous [,ȯr-kə-'dā-shəs] -adj

  1. of, relating to, or resembling the orchids
  2. showy, ostentatious

or·chi·ec·to·my [,ȯr-kē-'ek-tə-mē] -n

  1. surgical removal of one or both testes

or·chis ['ȯr-kəs] -n

  1. orchid
  2. any of a genus ( Orchis) of orchids with fleshy roots and a spurred lip

ord -abbr

  1. order
  2. ordnance

or·dain [ȯr-'dān] -vb, n

  1. to invest officially (as by the laying on of hands) with ministerial or priestly authority
  2. to establish or order by appointment, decree, or law : enact
    • we the people...do ordain and establish this Constitution -- U.S. Constitution
  3. destine, foreordain
  4. to issue an order

or·deal [ȯr-'dē(-ə)l, 'ȯr-,] -n

  1. a primitive means used to determine guilt or innocence by submitting the accused to dangerous or painful tests believed to be under supernatural control
    • ordeal by fire
  2. a severe trial or experience

or·der ['ȯr-dər] -vb, adj, n

  1. to put in order : arrange
  2. to give an order to : command
  3. destine, ordain
    • so order ed by the gods
  4. to command to go or come to a specified place
    • order ed back to the base
  5. to give an order for
    • order a meal
  6. to bring about order : regulate
  7. to issue orders : command
  8. to give or place an order

order [-ləs] -n, adj

  1. : a group of people united in a formal way: as
  2. a fraternal society
    • the Masonic Order
  3. a community under a religious rule
  4. one requiring members to take solemn vows
  5. a badge or medal of such a society
  6. a military decoration
  7. any of the several grades of the Christian ministry
  8. the office of a person in the Christian ministry
  9. ordination
  10. a rank, class, or special group in a community or society
  11. : a class of persons or things grouped according to quality, value, or natural characteristics: as
  12. a category of taxonomic classification ranking above the family and below the class
  13. the broadest category in soil classification
  14. rank, level
    • a statesman of the first order
  15. category, class
    • in emergencies of this order -- R. B. Westerfield
  16. the arrangement or sequence of objects or of events in time
    • listed the items in order of importance
    • the batting order
  17. a sequential arrangement of mathematical elements
  18. degree
  19. the number of times differentiation is applied successively
    • derivatives of higher order
  20. the order of the derivative of highest order
  21. the number of columns or rows or columns and rows in a magic square, determinant, or matrix
    • the order of a matrix with 2 rows and 3 columns is 2 by 3
  22. the number of elements in a finite mathematical group
  23. a sociopolitical system
    • was opposed to changes in the established order
  24. a particular sphere or aspect of a sociopolitical system
    • the present economic order
  25. a regular or harmonious arrangement
    • the order of nature
  26. a prescribed form of a religious service : rite
  27. the customary mode of procedure esp. in debate
    • point of order
  28. the state of peace, freedom from confused or unruly behavior, and respect for law or proper authority
    • promised to restore law and order
  29. a specific rule, regulation, or authoritative direction : command
  30. a style of building
  31. a type of column and entablature forming the unit of a style
  32. state or condition esp. with regard to functioning or repair
    • things were in terrible order
  33. a proper, orderly, or functioning condition
    • their passports were in order
    • the phone is out of order
  34. a written direction to pay money to someone
  35. a commission to purchase, sell, or supply goods or to perform work
  36. goods or items bought or sold
  37. an assigned or requested undertaking
    • landing men on the moon was a tall order
  38. order of the day
    • flat roofs were the order in the small villages

order arms -n

  1. a command to return the rifle to order arms from present arms or to drop the hand from a hand salute
  2. a position in the manual of arms in which the rifle is held vertically beside the right leg with the butt resting on the ground

or·dered ['ȯr-dərd] -adj

  1. : characterized by order: as
  2. marked by regularity or discipline
    • led an ordered life
  3. marked by regular or harmonious arrangement or disposition
    • an ordered landscape
    • the ordered crystal structure
  4. : having elements arranged or identified according to a rule: as
  5. having the property that every pair of different elements is related by a transitive relationship that is not symmetric
  6. having elements labeled by ordinal numbers
    • an ordered triple has a first, second, and third element

or·der·li·ness ['ȯrd-ər-lē-nəs] -n

  1. the quality or state of being orderly

or·der·ly [-lē] -adj, adv

  1. arranged or disposed in some order or pattern : regular
    • orderly rows of houses
  2. marked by order : tidy
    • keeps an orderly desk
  3. governed by law : regulated
    • an orderly universe
  4. methodical
    • an orderly mind
  5. well behaved : peaceful
    • an orderly crowd

orderly -n

  1. a soldier assigned to perform various services (as carrying messages) for a superior officer
  2. a hospital attendant who does routine or heavy work (as cleaning, carrying supplies, or moving patients)

order of battle

  1. the disposition of troops or ships ready for combat
  2. a tabular compilation of units, commanders, equipment, and their locations in a theater of operation

order of business

  1. a matter which must be dealt with : task
    • the budget was the first order of business at the committee meeting

order of magnitude

  1. a range of magnitude extending from some value to ten times that value

order of the day

  1. the business or tasks appointed for an assembly for a given day
  2. the characteristic or dominant feature or activity
    • growth and change are the order of the day in every field -- Ruth G. Strickland

or·di·nal ['ȯrd-nəl, 'ȯr-də-nəl] -n

  1. a book of rites for the ordination of deacons, priests, and bishops
  2. ordinal number

ordinal -adj

  1. of a specified order or rank in a series
  2. of or relating to a taxonomic order

ordinal number -n

  1. a number designating the place (as first, second, or third) occupied by an item in an ordered sequence
  2. a number assigned to an ordered set that designates both the order of its elements and its cardinal number

or·di·nance ['ȯrd-nən(t)s, 'ȯr-də-nən(t)s] -n

  1. an authoritative decree or direction : order
  2. a law set forth by a governmental authority
  3. a municipal regulation
  4. something ordained or decreed by fate or a deity
  5. a prescribed usage, practice, or ceremony

or·di·nand [,ȯr-də-'nand] -n

  1. a candidate for ordination

or·di·nary ['ȯr-də-,ner-ē] -n

  1. a prelate exercising original jurisdiction over a specified territory or group
  2. a clergyman appointed formerly in England to attend condemned criminals
  3. a judge of probate in some states of the U.S.
  4. the parts of the Mass that do not vary from day to day
  5. the regular or customary condition or course of things usu. used in the phrase out of the ordinary
  6. a meal served to all comers at a fixed price
  7. a tavern or eating house serving regular meals
  8. a common heraldic charge (as the bend) of simple form

ordinary [,ȯr-də-'ner-ə-lē] -adj, adv, n

  1. of a kind to be expected in the normal order of events : routine, usual
    • an ordinary day
  2. having or constituting immediate or original jurisdiction
  3. belonging to such jurisdiction
  4. of common quality, rank, or ability
    • an ordinary teenager
  5. deficient in quality : poor, inferior
    • ordinary wine

ordinarylanguage philosophy -n

  1. a trend in philosophical analysis that seeks to resolve philosophical perplexity by revealing sources of puzzlement in the misunderstanding of ordinary language

Ordinary level -n

  1. o level

ordinary seaman -n

  1. a seaman of some experience but not as skilled as an able seaman

ordinary share -n

  1. a share of common stock

or·di·nate ['ȯrd-nət, 'ȯr-də-nət, -,nāt] -n

  1. the Cartesian coordinate obtained by measuring parallel to the y-axis

or·di·na·tion [,ȯr-də-'nā-shən] -n

  1. the act or an instance of ordaining : the state of being ordained

ord·nance ['ȯrd-nən(t)s] -n

  1. military supplies including weapons, ammunition, combat vehicles, and maintenance tools and equipment
  2. a service of the army charged with the procuring, distributing, and safekeeping of ordnance
  3. cannon, artillery

or·do ['ȯr-(,)dō] -n

  1. a list of offices and feasts of the Roman Catholic Church for each day of the year

or·don·nance [,ȯr-də-'näⁿs] -n

  1. disposition of the parts (as of a literary composition) with regard to one another and the whole : arrangement

Or·do·vi·cian [,ȯr-də-'vi-shən] -adj, n

  1. of, relating to, or being the period between the Cambrian and the Silurian or the corresponding system of rocks

or·dure ['ȯr-jər] -n

  1. excrement
  2. something that is morally degrading

ore ['ȯr] -n

  1. a naturally occurring mineral containing a valuable constituent (as metal) for which it is mined and worked
  2. a source from which valuable matter is extracted
  3. see krona, krone at

Ore -abbr

  1. Oregon

ore·ad ['ȯr-ē-,ad, -ē-əd] -n

  1. any of the nymphs of mountains and hills in Greek mythology

orec·chi·et·te [ō-,rā-kē-'e-tā] -n

  1. small oval pasta

ore dressing -n

  1. mechanical preparation (as by crushing) and concentration (as by flotation) of ore

oreg·a·no [ə-'re-gə-,nō] -n

  1. a bushy perennial mint ( Origanum vulgare) that is used as a seasoning and a source of aromatic oil called also origanum wild marjoram
  2. any of several plants (genera Lippiaand Coleus) other than oregano of the vervain or mint families

Or·e·gon grape ['ȯr-i-gən-, 'är-, -,gän-] -n

  1. an evergreen shrub ( Mahonia aquifolium) of the barberry family that has yellow flowers, bears edible bluish-black berries, and is native to western No. America

Or·eo ['ȯr-ē-(,)ō, 'är-] -n

  1. a black person who adopts the characteristic mentality and behavior of white middle-class society

Ores·tes [ə-'res-(,)tēz, ȯ-] -n

  1. the son of Agamemnon and Clytemnestra who with his sister Electra avenges his father by killing his mother and her lover Aegisthus

org -abbr

  1. organic
  2. organization; organized

or·gan ['ȯr-gən] -n

  1. any of various musical instruments
  2. wind instrument
  3. a keyboard instrument in which sets of pipes are sounded by compressed air and produce a variety of timbres called also pipe organ
  4. reed organ
  5. an electronic keyboard instrument that approximates the sounds and resources of the pipe organ
  6. any of various similar cruder instruments
  7. a differentiated structure (as a heart, kidney, leaf, or stem) consisting of cells and tissues and performing some specific function in an organism
  8. bodily parts performing a function or cooperating in an activity
    • the eyes and related structures that make up the visual organ s
  9. a subordinate group or organization that performs specialized functions
    • the various organ s of government
  10. periodical

organ- -comb form

  1. organ
    • organo genesis
  2. organic
    • organo mercurial

or·gan·dy ['ȯr-gən-dē] -n

  1. a very fine transparent muslin with a stiff finish

or·gan·elle [,ȯr-gə-'nel] -n

  1. a specialized cellular part (as a mitochondrion, lysosome, or ribosome) that is analogous to an organ

or·gangrind·er ['ȯr-gən-,grīn-dər] -n

  1. one that cranks a hand organ
  2. a street musician who operates a barrel organ

or·gan·ic [ȯr-'ga-nik] -adj, adv, n

  1. instrumental
  2. of, relating to, or arising in a bodily organ
  3. affecting the structure of the organism
  4. of, relating to, or derived from living organisms
    • organic evolution
  5. of, relating to, yielding, or involving the use of food produced with the use of feed or fertilizer of plant or animal origin without employment of chemically formulated fertilizers, growth stimulants, antibiotics, or pesticides
    • organic farming
    • organic produce
  6. of, relating to, or containing carbon compounds
  7. relating to, being, or dealt with by a branch of chemistry concerned with the carbon compounds of living beings and most other carbon compounds
  8. forming an integral element of a whole : fundamental
    • incidental music rather than organic parts of the action -- Francis Fergusson
  9. having systematic coordination of parts : organized
    • an organic whole
  10. having the characteristics of an organism : developing in the manner of a living plant or animal
    • society is organic
  11. of, relating to, or constituting the law by which a government or organization exists

organic -n

  1. : an organic substance: as
  2. a fertilizer of plant or animal origin
  3. a pesticide whose active component is an organic compound or a mixture of organic compounds
  4. a food produced by organic farming

organic brain syndrome -n

  1. an acute or chronic mental dysfunction (as Alzheimer's disease) resulting chiefly from physical changes in brain structure and characterized esp. by impaired cognition

or·gan·i·cism [ȯr-'ga-nə-,si-zəm] -n, n or adj

  1. the explanation of life and living processes in terms of the levels of organization of living systems rather than in terms of the properties of their smallest components
  2. vitalism
  3. any of various theories that attribute to society or the universe as a whole an existence or characteristics analogous to those of a biological organism

or·ga·ni·sa·tion [,ȯr-gə-nə-'zā-shən, ,ȯrg-nə-] -n

(variant of organization)

  1. the act or process of organizing or of being organized
  2. the condition or manner of being organized
  3. association, society
    • charitable organization s
  4. an administrative and functional structure (as a business or a political party)
  5. the personnel of such a structure

or·gan·ism ['ȯr-gə-,ni-zəm] -n, adj, adv

  1. a complex structure of interdependent and subordinate elements whose relations and properties are largely determined by their function in the whole
  2. an individual constituted to carry on the activities of life by means of organs separate in function but mutually dependent : a living being

or·gan·ist ['ȯr-gə-nist] -n

  1. a person who plays the organ

or·ga·ni·za·tion [,ȯr-gə-nə-'zā-shən, ,ȯrg-nə-] -n

  1. the act or process of organizing or of being organized
  2. the condition or manner of being organized
  3. association, society
    • charitable organization s
  4. an administrative and functional structure (as a business or a political party)
  5. the personnel of such a structure

organization -adj

  1. characterized by complete conformity to the standards and requirements of an organization
    • an organization man

or·ga·ni·za·tion·al [-shnəl, -shə-nᵊl] -adj, adv

  1. of or relating to an organization : involving organization
    • the organizational state of a crystal
  2. organization

or·ga·nize ['ȯr-gə-,nīz] -vb, adj

  1. to cause to develop an organic structure
  2. to form into a coherent unity or functioning whole : integrate
    • trying to organize her thoughts
  3. to set up an administrative structure for
  4. to persuade to associate in an organization
  5. unionize
  6. to arrange by systematic planning and united effort
  7. to undergo physical or organic organization
  8. to arrange elements into a whole of interdependent parts
  9. to form an organization
  10. to form or persuade workers to join a union

organized -adj

  1. having a formal organization to coordinate and carry out activities
    • organized baseball
    • organized crime
  2. affiliated by membership in an organization (as a union)
    • organized steelworkers

or·ga·niz·er ['ȯr-gə-,nī-zər] -n

  1. one that organizes
  2. a region of a developing embryo or a substance produced by such a region that is capable of inducing a specific type of development in undifferentiated tissue called also inductor

or·gan·o·chlo·rine [,ȯr-gə-nō-'klȯr-,ēn, ȯr-,ga-nə-, -ən] -adj, n

  1. of, relating to, or being a chlorinated hydrocarbon and esp. one used as a pesticide (as aldrin, DDT, or dieldrin)

organ of Cor·ti [-'kȯr-tē]

  1. a complex epithelial structure in the cochlea that rests on the internal surface of the basilar membrane and in mammals is the chief part of the ear by which sound is directly perceived

or·gan·o·gen·e·sis [,ȯr-gə-nō-'je-nə-səs, ȯr-,ga-nə-] -n, adj

  1. the origin and development of bodily organs

or·gan·o·lep·tic [,ȯr-gə-nō-'lep-tik, ȯr-,ga-nə-] -adj, adv

  1. being, affecting, or relating to qualities (as taste, color, odor, and feel) of a substance (as a food or drug) that stimulate the sense organs
    • organoleptic research
  2. involving use of the sense organs
    • organoleptic evaluation of foods

or·gan·o·mer·cu·ri·al [,ȯr-gə-nō-(,)mər-'kyu̇r-ē-əl, ȯr-,ga-nə-] -n

  1. an organic compound or a pharmaceutical preparation containing mercury

or·gan·o·me·tal·lic [-mə-'ta-lik] -adj, n

  1. of, relating to, or being an organic compound that usu. contains a metal or metalloid bonded directly to carbon

or·ga·non ['ȯr-gə-,nän] -n

  1. an instrument for acquiring knowledge
  2. a body of principles of scientific or philosophic investigation

or·gan·o·phos·phate [,ȯr-gə-nō-'fäs-,fāt, ȯr-,ga-nō-] -n, adj

  1. an organophosphorus compound (as a pesticide)

or·gan·o·phos·pho·rus [-'fäs-f(ə-)rəs] -adj, n

  1. of, relating to, or being a phosphorus-containing organic compound and esp. a pesticide (as malathion) that acts by inhibiting cholinesterase

organpipe cactus -n

  1. any of several tall upright cacti (as Lemaireocereus thurberior L. marginatus) of the southwestern U.S. and adjacent Mexico that usu. branch at the base to form several upright stems

or·ga·num ['ȯr-gə-nəm] -n

  1. early polyphony of the late Middle Ages that consists of one or more voice parts accompanying the cantus firmus often in parallel motion at a fourth, fifth, or octave above or below
  2. a composition in this style
  3. organon

or·gan·za [ȯr-'gan-zə] -n

  1. a sheer dress fabric (as of silk or nylon) resembling organdy

or·gan·zine ['ȯr-gən-,zēn] -n

  1. a raw silk yarn used for warp threads in fine fabrics

or·gasm ['ȯr-,ga-zəm] -n, adj

  1. intense or paroxysmal excitement
  2. an explosive discharge of neuromuscular tensions at the height of sexual arousal that is usu. accompanied by the ejaculation of semen in the male and by vaginal contractions in the female

orgasm -vi

  1. to experience orgasm

or·geat ['ȯr-,zhä(t)] -n

  1. a sweet almond-flavored nonalcoholic syrup used as a cocktail ingredient or food flavoring

or·gi·as·tic [,ȯr-jē-'as-tik] -adj, adv

  1. of, relating to, or marked by orgies
  2. characterized by unrestrained emotion : frenzied

or·gone ['ȯr-,gōn] -n

  1. a vital energy held to pervade nature and be a factor in health in the theories of Wilhelm Reich

or·gu·lous ['ȯr-gyə-ləs, -gə-] -adj

  1. proud

or·gy ['ȯr-jē] -n

  1. secret ceremonial rites held in honor of an ancient Greek or Roman deity and usu. characterized by ecstatic singing and dancing
  2. drunken revelry
  3. a sexual encounter involving many people
  4. an excessive sexual indulgence
  5. excessive indulgence in something esp. to satisfy an inordinate appetite or craving
    • an orgy of destruction
    • a national orgy of thrill seeking and risk taking -- K. T. Greenfeld

orib·a·tid [ȯ-'ri-bə-təd, ,ȯr-ə-'ba-təd] -n, adj

  1. any of a superfamily (Oribatoidea) of small oval eyeless nonparasitic mites having a heavily sclerotized integument with a leathery appearance

ori·el window ['ȯr-ē-əl-] -n

  1. a large bay window projecting from a wall and supported by a corbel or bracket called also oriel

ori·ent ['ȯr-ē-ənt, -ē-,ent] -n

  1. east
  2. east
  3. a pearl of great luster
  4. the luster of a pearl

orient -adj

  1. oriental
  2. lustrous, sparkling
    • orient gems
  3. radiant, glowing
  4. rising in the sky

ori·ent ['ȯr-ē-,ent] -vt

  1. to cause to face or point toward the east
  2. to build (a church or temple) with the longitudinal axis pointing eastward and the chief altar at the eastern end
  3. to set or arrange in any determinate position esp. in relation to the points of the compass
  4. to ascertain the bearings of
  5. to set right by adjusting to facts or principles
  6. to acquaint with the existing situation or environment
  7. to direct (as a book or film) toward the interests of a particular group
  8. to cause the axes of the molecules of to assume the same direction

ori·en·tal [,ȯr-ē-'en-tᵊl] -adj, adv

  1. of, relating to, or situated in Asia
  2. of superior grade, luster, or value
  3. being corundum or sapphire but simulating another gem in color
  4. Asian
  5. of, relating to, or constituting the biogeographic region that includes Asia south and southeast of the Himalayas and the Malay Archipelago west of Wallace's line

Oriental -n

  1. Asian
  2. one who is a native of east Asia or is of east Asian descent
  3. oriental rug
  4. oriental shorthair

oriental fruit moth -n

  1. a small nearly cosmopolitan moth ( Grapholita molestasyn. Cydia molesta) prob. of Japanese origin whose larva is injurious to the twigs and fruit of orchard trees and esp. the peach called also oriental peach moth

Ori·en·ta·lia [,ȯr-ē-ən-'tāl-yə, -,en-, -'tā-lē-ə] -n pl

  1. materials concerning, characteristic of, or from Asia

ori·en·tal·ism [,ȯr-ē-'en-tə-,li-zəm] -n, n or adj

  1. something (as a style or manner) associated with or characteristic of Asia or Asians
  2. scholarship or learning in Asian subjects or languages

ori·en·tal·ize [-tə-,līz] -vb, n

  1. to make Asian : give Asian qualities to
  2. to adopt Asian characteristics

Oriental poppy -n

  1. an Asian perennial poppy ( Papaver orientale) that is commonly cultivated for its large showy flowers

Oriental rug -n

  1. a handwoven or hand-knotted one-piece rug or carpet made in a country of central or southern Asia called also Oriental carpet

Oriental shorthair -n

  1. a slender short-haired domestic cat of a breed resembling the Siamese in conformation but having a solid-colored coat in a wide range of colors

ori·en·tate ['ȯr-ē-ən-,tāt, -,en-] -vb

  1. to face or turn to the east
  2. orient

orientated -adj

  1. oriented

ori·en·ta·tion [,ȯr-ē-ən-'tā-shən, -,en-] -n, adj, adv

  1. the act or process of orienting or of being oriented
  2. the state of being oriented
  3. arrangement, alignment
  4. a usu. general or lasting direction of thought, inclination, or interest
  5. a person's self-identification as heterosexual, homosexual, or bisexual
    • sexual orientation
  6. change of position by organs, organelles, or organisms in response to external stimulus

ori·ent·ed ['ȯr-ē-,en-təd] -adj

  1. intellectually, emotionally, or functionally directed
    • humanistically oriented scholars
    • market- oriented production

ori·en·teer [,ȯr-ē-ən-'tir, -,en-] -n

  1. a person who engages in orienteering

ori·en·teer·ing [,ȯr-ē-ən-'tir-iŋ, -,en-] -n

  1. a cross-country race in which each participant uses a map and compass to navigate between checkpoints along an unfamiliar course

or·i·fice ['ȯr-ə-fəs, 'är-] -n, adj

  1. an opening (as a vent, mouth, or hole) through which something may pass

ori·flamme ['ȯr-ə-,flam, 'är-] -n

  1. a banner, symbol, or ideal inspiring devotion or courage

ori·ga·mi [,ȯr-ə-'gä-mē] -n

  1. the Japanese art or process of folding squares of paper into representational shapes

orig·a·num [ə-'ri-gə-nəm] -n

  1. any of several aromatic mints (esp. genus Origanum) used as seasonings
  2. oregano

or·i·gin ['ȯr-ə-jən, 'är-] -n

  1. ancestry, parentage
  2. rise, beginning, or derivation from a source
  3. the point at which something begins or rises or from which it derives
    • the origin of the custom
  4. something that creates, causes, or gives rise to another
    • a spring is the origin of the brook
  5. the more fixed, central, or larger attachment of a muscle
  6. the intersection of coordinate axes

orig·i·nal [ə-'rij-ə-nᵊl, -'rij-nəl] -n

  1. the source or cause from which something arises
  2. originator
  3. that from which a copy, reproduction, or translation is made
  4. a work composed firsthand
  5. a person of fresh initiative or inventive capacity
  6. a unique or eccentric person

original -adj

  1. of, relating to, or constituting an origin or beginning : initial
    • the original part of the house
  2. not secondary, derivative, or imitative
    • an original composition
  3. being the first instance or source from which a copy, reproduction, or translation is or can be made
  4. independent and creative in thought or action : inventive
    • an original artist

original equipment manufacturer -n

  1. oem

orig·i·nal·i·ty [ə-,ri-jə-'na-lə-tē] -n

  1. the quality or state of being original
  2. freshness of aspect, design, or style
  3. the power of independent thought or constructive imagination

orig·i·nal·ly [ə-'ri-jə-nᵊl-ē; -'rij-nə-lē, -'ri-jən-] -adv

  1. by origin or derivation : inherently
  2. in the beginning : in the first place : initially
  3. in a fresh or original manner

original sin -n

  1. the state of sin that according to Christian theology characterizes all human beings as a result of Adam's fall
  2. a wrong of great magnitude
    • the original sin of slavery

orig·i·nate [ə-'ri-jə-,nāt] -vb, n

  1. to give rise to : initiate
  2. to take or have origin : begin

orig·i·na·tive [ə-'ri-jə-,nā-tiv, -nə-] -adj, adv

  1. having ability to originate : creative

Oring ['ō-,riŋ] -n

  1. a ring (as of synthetic rubber) used as a gasket

ori·ole ['ȯr-ē-,ōl, -ē-əl] -n

  1. any of various usu. brightly colored Old World passerine birds (family Oriolidae and esp. genus Oriolus)
  2. any of various New World passerine birds (family Icteridae and esp. genus Icterus) of which the males are usu. black and yellow or black and orange

Ori·on [ə-'rī-ən, ȯ-] -n

  1. a constellation on the equator east of Taurus represented on charts by the figure of a hunter with belt and sword
  2. a giant hunter slain by Artemis in Greek mythology

ori·sha ['ȯr-ə-,shä] -n

  1. a Yoruba deity
  2. one identified with a Roman Catholic saint in Santeria

or·is·mol·o·gy [,ȯr-əz-'mä-lə-jē, ,är-] -n, adj

  1. the science of defining technical terms

or·i·son ['ȯr-ə-sən, 'är-, -zən] -n

  1. prayer

Ori·ya [ȯ-'rē-ə] -n

  1. the Indo-Aryan language of Orissa, India

Or·lean·ist ['ȯr-lē-ə-nist, ȯr-'lē-(ə-)nist] -n

  1. a supporter of the Orleans family in its claim to the throne of France by descent from a younger brother of Louis XIV

Or·lon ['ȯr-,län] -trademark

  1. used for an acrylic fiber

or·lop deck ['ȯr-,läp-] -n

  1. the lowest deck in a ship having four or more decks

Or·mazd ['ȯr-(,)məzd, -,mazd] -n

  1. ahura mazda

or·mo·lu ['ȯr-mə-,lü] -n

  1. golden or gilded brass or bronze used for decorative purposes (as in mounts for furniture)

or·na·ment ['ȯr-nə-mənt] -n

  1. a useful accessory
  2. something that lends grace or beauty
  3. a manner or quality that adorns
  4. one whose virtues or graces add luster to a place or society
  5. the act of adorning or being adorned
  6. an embellishing note not belonging to the essential harmony or melody called also embellishment fioritura
  7. to provide with ornament : embellish

or·na·men·tal [,ȯr-nə-'men-tᵊl] -adj, adv

  1. of, relating to, or serving as ornament
  2. grown as an ornamental

ornamental -n

  1. a decorative object
  2. a plant cultivated for its beauty rather than for use

or·na·men·ta·tion [,ȯr-nə-mən-'tā-shən, -,men-] -n

  1. something that ornaments : embellishment
  2. the act or process of ornamenting : the state of being ornamented

or·nate [ȯr-'nāt] -adj, adv, n

  1. marked by elaborate rhetoric or florid style
  2. elaborately or excessively decorated
    • an ornate mantle

or·nery ['ȯr-nə-rē, 'är-; 'ȯrn-rē, 'ärn-] -adj, n

  1. having an irritable disposition : cantankerous

ornith- -comb form

  1. bird
    • ornitho logy

or·nith·ic [ȯr-'ni-thik] -adj

  1. of, relating to, or characteristic of birds

or·ni·thine ['ȯr-nə-,thēn] -n

  1. a crystalline amino acid C 5H 12N 2O 2that functions esp. in urea production as a carrier by undergoing conversion to citrulline and then arginine in reaction with ammonia and carbon dioxide followed by recovery along with urea by enzymatic hydrolysis of arginine

or·nith·is·chi·an [,ȯr-nə-'this-kē-ən] -n, adj

  1. any of an order (Ornithischia) of herbivorous dinosaurs (as a stegosaurus) that have the pubis of the pelvis rotated backward to a position parallel and close to the ischium

or·ni·thol·o·gy [,ȯr-nə-'thä-lə-jē] -n, adj, adv

  1. a treatise on ornithology
  2. a branch of zoology dealing with birds

or·nith·o·pod [ȯr-'ni-thə-,päd, 'ȯr-ni-thə-] -n

  1. any of a suborder (Ornithopoda) of bipedal ornithischian dinosaurs (as a hadrosaur) with digitigrade walking limbs usu. having only three functional toes

or·ni·thop·ter ['ȯr-nə-,thäp-tər] -n

  1. an aircraft designed to derive its chief support and propulsion from flapping wings

or·ni·tho·sis [,ȯr-nə-'thō-səs] -n

  1. psittacosis

oro- -comb form

  1. mountain
    • oro graphy
  2. mouth
    • oro pharynx

oro·gen·e·sis [,ȯr-ə-'je-nə-səs] -n, adj

  1. orogeny

orog·e·ny [ȯ-'rä-jə-nē] -n, adj

  1. the process of mountain formation esp. by folding of the earth's crust

oro·graph·ic [,ȯr-ə-'gra-fik] -adj

  1. of or relating to mountains
  2. associated with or induced by the presence of mountains
    • orographic rainfall

orog·ra·phy [ȯ-'rä-grə-fē] -n

  1. a branch of physical geography that deals with mountains

Oro·mo [ȯ-'rō-(,)mō, ō-] -n

  1. a member of a Cushitic-speaking people of southern Ethiopia and adjacent parts of Kenya
  2. the Cushitic language of the Oromo

oro·pha·ryn·geal [,ȯr-ə-,fa-rən-'jē-əl, -fə-'rin-j(ē-)əl] -adj

  1. of or relating to the oropharynx
  2. of or relating to the mouth and pharynx

oro·phar·ynx [-'fa-riŋ(k)s] -n

  1. the part of the pharynx that is below the soft palate and above the epiglottis and is continuous with the mouth

oro·tund ['ȯr-ə-,tənd, 'är-] -adj, n

  1. marked by fullness, strength, and clarity of sound : sonorous
    • an orotund voice
  2. pompous, bombastic
    • an orotund speech

or·phan ['ȯr-fən] -n, adj

  1. a child deprived by death of one or usu. both parents
  2. a young animal that has lost its mother
  3. one deprived of some protection or advantage
    • orphan s of the storm
  4. a first line (as of a paragraph) separated from its related text and appearing at the bottom of a printed page or column

orphan ['ȯr-fə-niŋ, 'ȯrf-niŋ] -vt

  1. to cause to become an orphan

or·phan·age ['ȯr-fə-nij, 'ȯrf-nij] -n

  1. the state of being an orphan
  2. an institution for the care of orphans

orphan drug -n

  1. a drug that is not developed or marketed because its extremely limited use makes it unprofitable

orphan's court -n

  1. a probate court with jurisdiction in some states over the affairs of minors and the administration of estates

Or·pheus ['ȯr-,fyüs, -fē-əs] -n

  1. a poet and musician in Greek mythology who almost rescues his wife Eurydice from Hades by charming Pluto and Persephone with his lyre

or·phic ['ȯr-fik] -adj, adv

  1. of or relating to Orpheus or the rites or doctrines ascribed to him
  2. mystic, oracular
  3. fascinating, entrancing

Or·phism ['ȯr-,fi-zəm] -n

  1. a mystic Greek religion offering initiates purification of the soul from innate evil and release from the cycle of reincarnation

or·phrey ['ȯr-frē] -n

  1. elaborate embroidery
  2. a piece of such embroidery
  3. an ornamental border or band esp. on an ecclesiastical vestment

or·pi·ment ['ȯr-pə-mənt] -n

  1. a rare orange to lemon-yellow mineral consisting of a native trisulfide of arsenic

or·pine ['ȯr-pən] -n

  1. an herb ( Sedum telephiumof the family Crassulaceae, the orpine family) that has fleshy leaves and pink or purple flowers and was formerly used in folk medicine
  2. sedum

Or·ping·ton ['ȯr-piŋ-tən] -n

  1. any of an English breed of large deep-chested domestic chickens

or·rery ['ȯr-ər-ē, 'är-] -n

  1. an apparatus showing the relative positions and motions of bodies in the solar system by balls moved by a clockwork

or·ris ['ȯr-əs, 'är-] -n

  1. orrisroot

or·ris·root [-,rüt, -,ru̇t] -n

  1. the fragrant rootstock of any of three European irises ( Iris florentina, I. germanica,and I. pallida) used esp. in perfumery

ort ['ȯrt] -n

  1. a morsel left at a meal : scrap

orth- -comb form

  1. straight : upright : vertical
    • ortho grade
  2. perpendicular
    • ortho rhombic
  3. correct : corrective
    • orth odontia
  4. hydrated or hydroxylated to the highest degree
    • ortho phosphoric acid
  5. involving substitution at or characterized by or having the relationship of two neighboring positions in the benzene ring
    • ortho- xylene

or·thi·con ['ȯr-thi-,kän] -n

  1. a camera tube similar to but more sensitive than an iconoscope in which the charges are scanned by a low-velocity beam

or·tho ['ȯr-(,)thō] -adj

  1. orthochromatic

or·tho·cen·ter ['ȯr-thə-,sen-tər] -n

  1. the common intersection of the three altitudes of a triangle or their extensions or of the several altitudes of a polyhedron provided these latter exist and meet in a point

or·tho·chro·mat·ic [,ȯr-thə-krō-'ma-tik] -adj

  1. of, relating to, or producing tone values of light and shade in a photograph that correspond to the tones in nature
  2. sensitive to all colors except red

or·tho·clase ['ȯr-thə-,klās, -,klāz] -n

  1. a monoclinic mineral of the feldspar group consisting of a silicate of potassium and aluminum

or·tho·don·tia [,ȯr-thə-'dän(t)-sh(ē-)ə] -n

  1. orthodontics

or·tho·don·tics [-'dän-tiks] -n pl but sing in constr, adj, adv, n

  1. a branch of dentistry dealing with irregularities of the teeth (as malocclusion) and their correction (as by braces)

or·tho·dox ['ȯr-thə-,däks] -adj, adv

  1. conforming to established doctrine esp. in religion
  2. conventional
  3. : of, relating to, or constituting any of various conservative religious or political groups: as
  4. eastern orthodox
  5. of or relating to Orthodox Judaism

orthodox -n

  1. one that is orthodox
  2. a member of an Eastern Orthodox church

Orthodox Judaism -n

  1. Judaism that adheres to the Torah and Talmud as interpreted in an authoritative rabbinic law code and applies their principles and regulations to modern living

or·tho·doxy ['ȯr-thə-,däk-sē] -n

  1. the quality or state of being orthodox
  2. an orthodox belief or practice
  3. Eastern Orthodox Christianity
  4. orthodox judaism

or·tho·epy ['ȯr-thə-,we-pē, ȯr-'thō-ə-pē] -n, adj, adv

  1. the customary pronunciation of a language
  2. the study of the pronunciation of a language

or·tho·gen·e·sis [,ȯr-thə-'je-nə-səs] -n, adj, adv

  1. variation of organisms in successive generations that in some esp. former evolutionary theories takes place in some predestined direction resulting in progressive evolutionary trends independent of external factors

or·thog·o·nal [ȯr-'thä-gə-nᵊl] -adj, n, adv

  1. intersecting or lying at right angles
  2. having perpendicular slopes or tangents at the point of intersection
    • orthogonal curves
  3. : having a sum of products or an integral that is zero or sometimes one under specified conditions: as
  4. having the integral of the product of each pair of functions over a specific interval equal to zero
  5. having the scalar product equal to zero
  6. having the sum of products of corresponding elements in any two rows or any two columns equal to one if the rows or columns are the same and equal to zero otherwise : having a transpose with which the product equals the identity matrix
  7. having a matrix that is orthogonal : preserving length and distance
  8. composed of mutually orthogonal elements
    • an orthogonal basis of a vector space
  9. statistically independent

or·thog·o·nal·ize [ȯr-'thä-gə-nə-,līz] -vt, n

  1. to make orthogonal

or·tho·grade ['ȯr-thə-,grād] -adj

  1. walking with the body upright

or·tho·graph·ic [,ȯr-thə-'gra-fik] -adj, adv

  1. of, relating to, being, or prepared by orthographic projection
    • an orthographic map
  2. of or relating to orthography
  3. correct in spelling

orthographic projection -n

  1. projection of a single view of an object (as a view of the front) onto a drawing surface in which the lines of projection are perpendicular to the drawing surface
  2. the representation of related views of an object as if they were all in the same plane and projected by orthographic projection

or·thog·ra·phy [ȯr-'thä-grə-fē] -n

  1. the art of writing words with the proper letters according to standard usage
  2. the representation of the sounds of a language by written or printed symbols
  3. a part of language study that deals with letters and spelling

or·tho·mo·lec·u·lar [,ȯr-thə-mə-'le-kyə-lər] -adj

  1. relating to, based on, using, or being a theory according to which disease may be cured by providing the optimum amounts of substances (as vitamins) normally present in the body
    • orthomolecular therapy
    • orthomolecular psychiatry

or·tho·myxo·vi·rus [,ȯr-thō-'mik-sə-,vī-rəs] -n

  1. any of a family ( Orthomyxoviridae) of single-stranded RNA viruses that have a spherical or filamentous virion with numerous surface projections of glycoprotein and include the causative agents of influenza

or·tho·nor·mal [,ȯr-thə-'nȯr-məl] -adj

  1. orthogonal with the integral of the square of each function over a specified interval equal to one
  2. being or composed of orthogonal elements of unit length
    • orthonormal basis of a vector space

or·tho·pe·dic [,ȯr-thə-'pē-dik] -adj, adv

  1. of, relating to, or employed in orthopedics
  2. marked by or affected with a skeletal deformity, disorder, or injury

or·tho·pe·dics [-'pē-diks] -n pl but sing or pl in constr, n

  1. a branch of medicine concerned with the correction or prevention of deformities, disorders, or injuries of the skeleton and associated structures (as tendons and ligaments)

or·tho·phos·phate [,ȯr-thə-'fäs-,fāt] -n

  1. a salt or ester of orthophosphoric acid

or·tho·phos·pho·ric acid [,ȯr-thə-,fäs-'fȯr-ik-, -'fär-; -'fäs-f(ə-)rik-] -n

  1. phosphoric acid

or·tho·psy·chi·a·try [-sə-'kī-ə-trē, -(,)sī-] -n, adj

  1. psychiatry concerned esp. with the prevention and treatment of mental and behavioral disorders in youth

or·thop·tera [ȯr-'thäp-tə-rə] -n pl

  1. insects that are orthopterans

or·thop·ter·an [ȯr-'thäp-tə-rən] -n, adj, n or adj

  1. any of an order (Orthoptera) of insects (as crickets and grasshoppers) characterized by biting mouthparts, two pairs of wings or none, enlarged hind femurs, and an incomplete metamorphosis

or·tho·rhom·bic [,ȯr-thə-'räm-bik] -adj

  1. of, relating to, or constituting a system of crystallization characterized by three unequal axes at right angles to each other

or·tho·scop·ic [-'skä-pik] -adj

  1. giving an image in correct and normal proportions

or·tho·sis [ȯr-'thō-səs] -n

  1. orthotic

or·tho·stat·ic [,ȯr-thə-'sta-tik] -adj

  1. of, relating to, or caused by an upright posture
    • orthostatic hypotension

or·thot·ic [ȯr-'thä-tik] -n

  1. a device (as a brace or splint) for supporting, immobilizing, or treating muscles, joints, or skeletal parts which are weak, ineffective, deformed, or injured

or·thot·ics [-tiks] -n pl but sing in constr, adj, n

  1. a branch of mechanical and medical science that deals with the design and fitting of orthotics

or·thot·ro·pous [ȯr-'thä-trə-pəs] -adj

  1. having the ovule straight and upright with the micropyle at the apex

or·to·lan ['ȯr-tə-lən] -n

  1. an Old World bunting ( Emberiza hortulana) having a greenish-gray head and breast, streaky brown back and wings, and a yellow throat

ORV -abbr

  1. off-road vehicle

Or·vie·to [ȯr-'vyā-(,)tō] -n

  1. a usu. dry Italian white wine

oryx ['ȯr-iks, 'är-] -n

  1. any of a small genus (Oryx) of large heavily built African and Arabian antelopes that have a light-colored coat with dark conspicuous markings esp. on the face

or·zo ['ȯrd-(,)zō] -n

  1. rice-shaped pasta