zeal ['zēl] -n

  1. eagerness and ardent interest in pursuit of something : fervor
    • her zeal to succeed strained her relationships

zeal·ot ['ze-lət] -n

  1. a member of a fanatical sect arising in Judea during the first century a.d.and militantly opposing the Roman domination of Palestine
  2. a zealous person
  3. a fanatical partisan
    • a religious zealot

zeal·ot·ry ['ze-lə-trē] -n

  1. excess of zeal : fanatical devotion

zeal·ous ['ze-ləs] -adj, adv, n

  1. filled with or characterized by zeal : marked by fervent partisanship for a person, a cause, or an ideal
    • zealous missionaries

ze·a·tin ['zē-ə-tən] -n

  1. a cytokinin C 10H 13N 5O first isolated from the endosperm of Indian corn

ze·a·xan·thin [,zē-ə-'zan-thən] -n

  1. an isomer of lutein occurring esp. in fruits and vegetables (as spinach and corn)

ze·bra ['zē-brə, Canad & Brit also 'ze-] -n, adj or n

  1. any of several fleet African mammals ( Equus burchelli, E. grevyi,and E. zebra) related to the horse but distinctively and conspicuously patterned in stripes of black or dark brown and white or buff
  2. referee
  3. zebra crossing

ze·bra crossing ['ze-brə-, 'zē-] -n

  1. a crosswalk marked by a series of broad white stripes to indicate a crossing point at which pedestrians have the right of way

zebra finch -n

  1. a small Australian waxbill ( Taeniopygia guttatasyn. Poephila guttata) that is chiefly gray above and white below with a red or orange bill, a black-and-white barred tail, and in the male a black-barred throat and that is often kept as a cage bird

zebra fish -n

  1. any of various barred fishes
  2. a very small blue-and-silver-striped Indian danio ( Danio reriosyn. Brachydanio rerio) often kept in the tropical aquarium

zebra mussel -n

  1. a chiefly freshwater Eurasian lamellibranch mollusk ( Dreissena polymorpha) that was accidentally introduced into the Great Lakes and has spread to other waterways where it colonizes and clogs water intake pipes and competes with native fish for food

ze·brano [zə-'bra-nō] -n

  1. zebrawood

ze·bra·wood ['zē-brə-,wu̇d, 'ze-] -n

  1. : any of several trees or shrubs having mottled or striped wood: as
  2. a tall So. American timber tree ( Astronium fraxinifolium) of the cashew family
  3. a tall western African timber tree ( Microberlinia brazzavillensis) of the legume family
  4. the wood of a zebrawood

ze·bu ['zē-(,)bü, -(,)byü] -n

  1. any of various breeds of domestic oxen developed in India that are often considered conspecific with the common ox ( Bos taurus) or sometimes as a separate species ( B. indicus) and are characterized by a large fleshy hump over the shoulders, a dewlap, pendulous ears, and marked resistance to the injurious effects of heat and insect attack

Zeb·u·lun ['ze-byə-lən] -n

  1. a son of Jacob and the traditional eponymous ancestor of one of the tribes of Israel

zec·chi·no [ze-'kē-(,)nō, tse-] -n

  1. sequin

Zech -abbr

  1. Zechariah

Zech·a·ri·ah [,ze-kə-'rī-ə] -n

  1. a Hebrew prophet of the sixth century b.c.
  2. a prophetic book of canonical Jewish and Christian Scripture

ze·chin ['ze-kən, ze-'kēn] -n

  1. sequin

zed ['zed] -n

  1. the letter z

zee ['zē] -n

  1. the letter z

Zee·man effect ['zā-,män-, -mən-] -n

  1. the splitting of a single spectral line into two or more lines of different frequencies observed when radiation (as light) originates in a magnetic field

ze·in ['zē-ən] -n

  1. a protein from Indian corn that lacks lysine and tryptophan and is used esp. in making textile fibers, plastics, printing inks, coatings, and adhesives and sizes

zeit·ge·ber ['tsīt-,gā-bər, 'zīt-] -n

  1. an environmental agent or event (as the occurrence of light or dark) that provides the stimulus setting or resetting a biological clock of an organism

zeit·geist ['tsīt-,gīst, 'zīt-] -n

  1. the general intellectual, moral, and cultural climate of an era

zel·ko·va ['zel-kə-və, zel-'kō-və] -n

  1. a tall widely spreading Japanese tree ( Zelkova serrata) of the elm family that is often used as an ornamental and shade tree in place of the American elm because of its resistance to Dutch elm disease

zemst·vo ['zem(p)st-(,)vō, -və] -n

  1. one of the district and provincial assemblies established in Russia in 1864

Zen ['zen] -n

  1. a Japanese sect of Mahayana Buddhism that aims at enlightenment by direct intuition through meditation

ze·na·na [zə-'nä-nə] -n

  1. harem

ZendAves·ta [,zend-ə-'ves-tə] -n

  1. avesta

ze·ner diode ['zē-nər-, 'ze-] -n

  1. a silicon semiconductor device used esp. as a voltage regulator

ze·nith ['zē-nəth, Canad also & Brit usu 'ze-nəth, -nith] -n

  1. the point of the celestial sphere that is directly opposite the nadir and vertically above the observer
  2. the highest point reached in the heavens by a celestial body
  3. culminating point : acme
    • at the zenith of his powers -- John Buchan

ze·nith·al [-nə-thəl] -adj

  1. of, relating to, or located at or near the zenith
  2. showing correct directions from the center
    • a zenithal map

ze·o·lite ['zē-ə-,līt] -n, adj

  1. any of various hydrous silicates that are analogous in composition to the feldspars, occur as secondary minerals in cavities of lavas, and can act as ion-exchangers
  2. any of various natural or synthesized silicates of similar structure used esp. in water softening and as adsorbents and catalysts

Zeph -abbr

  1. Zephaniah

Zeph·a·ni·ah [,ze-fə-'nī-ə] -n

  1. a Hebrew prophet of the seventh century b.c.
  2. an apocalyptic book of canonical Jewish and Christian Scripture

zeph·yr ['ze-fər] -n

  1. a breeze from the west
  2. a gentle breeze
  3. any of various lightweight fabrics and articles of clothing

Zeph·y·rus ['ze-fə-rəs] -n

  1. the Greek god of the west wind

zep·pe·lin ['ze-p(ə-)lən] -n

  1. a rigid airship consisting of a cylindrical trussed and covered frame supported by internal gas cells
  2. airship

zep·to- -comb form

  1. one sextillionth (10 21) part of
    • zepto second

zep·to·sec·ond ['zep-tə-,se-kənd, -kənt] -n

  1. one sextillionth of a second

zerk ['zərk] -n

  1. a grease fitting

ze·ro ['zē-(,)rō, 'zir-(,)ō] -n

  1. the arithmetical symbol 0 or denoting the absence of all magnitude or quantity
  2. additive identity
  3. the number between the set of all negative numbers and the set of all positive numbers
  4. a value of an independent variable that makes a function equal to zero
    • 2 and 2 are zero s of f(x)x 2 4
  5. the point of departure in reckoning
  6. the point from which the graduation of a scale (as of a thermometer) begins
  7. the temperature represented by the zero mark on a thermometer
  8. the setting or adjustment of the sights of a firearm that causes it to shoot to point of aim at a desired range
  9. an insignificant person or thing : nonentity
  10. a state of total absence or neutrality
  11. the lowest point : nadir
  12. something arbitrarily or conveniently designated zero

zero -adj

  1. of, relating to, or being a zero
  2. having no magnitude or quantity : not any
    • zero growth
    • zero tolerance
  3. having no phonetic manifestation
    • the zero modification in the past tense of cut
  4. having no modified inflectional form
    • a zero plural
  5. limiting vision to 50 feet (15 meters) or less
  6. limited to 165 feet (50.3 meters) or less
  7. to determine or adjust the zero of (as a rifle)
  8. to concentrate firepower on the exact range of usu. used with in
  9. to bring to bear on the exact range of a target usu. used with in
  10. to adjust fire on a specific target usu. used with in
  11. to close in on or focus attention on an objective usu. used with in
    • investigators are zero ing in on a suspect

zerobased -adj

  1. having each item justified on the basis of cost or need
    • zerobased budgeting

zero coupon -adj

  1. of, relating to, or being an investment security that is sold at a deep discount, is redeemable at face value on maturity, and that pays no periodic interest
    • zero coupon municipal bonds

zero gravity -n

  1. the state or condition of lacking apparent gravitational pull : weightlessness

zero hour -n

  1. the hour at which a planned military operation is scheduled to start
  2. the time at which a usu. significant or notable event is scheduled to take place
  3. a time when a vital decision or decisive change must be made

zerosum -adj

  1. of, relating to, or being a situation (as a game or relationship) in which a gain for one side entails a corresponding loss for the other side
    • dividing up the budget is a zerosum game

ze·roth ['zē-(,)rōth, 'zir-(,)ōth] -adj

  1. being numbered zero in a series
  2. zero
    • the zeroth power of a number

zero tillage -n

  1. no-tillage

zero vector -n

  1. a vector which is of zero length and all of whose components are zero

zerozero -adj

  1. characterized by or being atmospheric conditions that reduce ceiling and visibility to zero
  2. limited to zero by atmospheric conditions

zest ['zest] -n, adj, adv

  1. a piece of the peel of a citrus fruit (as an orange or lemon) used as flavoring
  2. an enjoyably exciting quality : piquancy
    • adds zest to the performance
  3. keen enjoyment : relish, gusto
    • has a zest for living

zest·er ['zes-tər] -n

  1. a small utensil for peeling zest (as of a lemon)

zesty ['zes-tē] -adj, adv

  1. having or characterized by zest : appealingly piquant or lively
    • a zesty sauce
    • zesty humor

ze·ta ['zā-tə, 'zē-] -n

  1. the 6th letter of the Greek alphabet

zet·ta- -comb form

  1. sextillion (10 21)
    • zetta byte

zet·ta·byte ['ze-tə-,bīt] -n

  1. one sextillion bytes

zeug·ma ['züg-mə] -n

  1. the use of a word to modify or govern two or more words usu. in such a manner that it applies to each in a different sense or makes sense with only one (as in opened the door and her heart to the homeless boy)

Zeus ['züs] -n

  1. the king of the gods and husband of Hera in Greek mythology