o [] -n

  1. the 15th letter of the English alphabet
  2. a graphic representation of this letter
  3. a speech counterpart of orthographic o
  4. a graphic device for reproducing the letter o
  5. one designated oesp. as the 15th in order or class
  6. something shaped like the letter O
  7. zero
  8. ocean
  9. ohm
  10. old
  11. order
  12. over

O [(')ō] -interj

(variant of oh)

  1. used to express an emotion (as surprise or desire) or in response to physical stimuli
  2. used in direct address
    • oh, waiter Will you come here, please?
  3. used to express acknowledgment or understanding of a statement
  4. used to introduce an example or approximation
  5. zero

oaf ['ōf] -n, adj, adv

  1. a stupid person : boob
  2. a big clumsy slow-witted person

oak ['ōk] -n, adj

  1. any of a genus ( Quercus) of trees or shrubs of the beech family that produce acorns
  2. any of various plants related to or resembling the oaks
  3. the tough hard durable wood of an oak tree
  4. the leaves of an oak used as decoration

oak apple -n

  1. a large round gall produced on oak leaves and twigs by a gall wasp (esp. Amphibolips confluenta)

oakleaf cluster -n

  1. a bronze or silver cluster of oak leaves and acorns added to various military decorations to signify a second or subsequent award of the basic decoration

oak·moss ['ōk-,mȯs] -n

  1. any of several lichens (as Evernia prunastri) that grow on oak trees and yield a resin used in perfumery

oa·kum ['ō-kəm] -n

  1. loosely twisted hemp or jute fiber impregnated with tar or a tar derivative and used in caulking seams and packing joints

oak wilt -n

  1. a destructive disease of oak trees that is caused by a fungus ( Ceratocystis fagacearum) and is characterized by wilting, discoloration, and defoliation

oar ['ȯr] -n, adj

  1. a long pole with a broad blade at one end used for propelling or steering a boat
  2. oarsman
  3. to propel with or as if with oars : row
  4. to progress by or as if by using oars

oar·fish ['ȯr-,fish] -n

  1. a marine bony fish ( Regalecus glesne) of subtropical waters with a narrow soft body from 20 to 30 feet (6 to 9 meters) long, a red dorsal fin running the entire length of the body, and red-tipped anterior rays rising above the head

oar·lock [-,läk] -n

  1. a usu. U-shaped device for holding an oar in place

oars·man ['ȯrz-mən] -n

  1. one who rows esp. in a racing crew

oars·wom·an [-,wu̇-mən] -n

  1. a woman who is an oarsman

OAS -abbr

  1. Organization of American States

OASDI -abbr

  1. Old-Age, Survivors, and Disability Insurance

oa·sis [ō-'ā-səs] -n

  1. a fertile or green area in an arid region (as a desert)
  2. something that provides refuge, relief, or pleasant contrast

oast ['ōst] -n

  1. a usu. conical kiln used for drying hops, malt, or tobacco called also oast*house -has

oat ['ōt] -n

  1. any of several grasses (genus Avena)
  2. a widely cultivated cereal grass ( A. sativa)
  3. a crop or plot of the oat
  4. the seed of an oat usu. used in pl. but sing. or pl. in constr.
  5. a reed instrument made of an oat straw

oat·cake ['ōt-,kāk] -n

  1. a thin flat oatmeal cake

oat cell -n

  1. any of the small round or oval cells with a high ratio of nuclear protoplasm to cytoplasm that resemble oat grains and are characteristic of a small-cell lung cancer

oat·en ['ō-tᵊn] -adj

  1. of or relating to oats, oat straw, or oatmeal

oat·er ['ō-tər] -n

  1. western

oat grass -n

  1. wild oat
  2. any of several grasses resembling the oat

oath ['ōth] -n

  1. a solemn usu. formal calling upon God or a god to witness to the truth of what one says or to witness that one sincerely intends to do what one says
  2. a solemn attestation of the truth or inviolability of one's words
  3. something (as a promise) corroborated by an oath
  4. an irreverent or careless use of a sacred name
  5. swearword

oat·meal ['ōt-,mēl, ōt-'mēl] -n

  1. meal made from oats
  2. rolled oats
  3. porridge made from ground or rolled oats

OAU -abbr

  1. Organization of African Unity