oo·cyst ['ō-ə-,sist] -n

  1. zygote
  2. a sporozoan zygote undergoing sporogenous development

oo·cyte ['ō-ə-,sīt] -n

  1. an egg before maturation : a female gametocyte

OOD -abbr

  1. officer of the deck

oo·dles ['ü-dᵊlz] -n pl but sing or pl in constr

  1. a great quantity : lot

oog·a·mous [ō-'ä-gə-məs] -adj, n

  1. having or involving a small motile male gamete and a large immobile female gamete

oo·gen·e·sis [,ō-ə-'je-nə-səs] -n, adj

  1. formation and maturation of the egg

oo·go·ni·um [,ō-ə-'gō-nē-əm] -n, adj

  1. a female sexual organ in various algae and fungi that corresponds to the archegonium of ferns and mosses
  2. a descendant of a primordial germ cell that gives rise to oocytes

ooh [] -interj

  1. used to express amazement, joy, or surprise
  2. to exclaim in amazement, joy, or surprise
    • ooh ing and aahing over the new automobiles

oo·lite ['ō-ə-,līt] -n, adj

  1. a rock consisting of small round grains usu. of calcium carbonate cemented together

ool·o·gist [ō-'ä-lə-jist] -n

  1. a person specializing in the study of birds' eggs
  2. a collector of birds' eggs

oo·long ['ü-,lȯŋ] -n

  1. tea made from leaves that have been partially fermented before firing

oom·pah ['üm-(,)pä, 'u̇m-] -n, vb

  1. a repeated rhythmic bass accompaniment esp. in a band
  2. music featuring such accompaniment

oomph ['u̇m(p)f] -n

  1. personal charm or magnetism : glamour
  2. sex appeal
  3. punch, vitality

oo·pho·rec·to·my [,ō-ə-fə-'rek-tə-mē] -n

  1. the surgical removal of an ovary called also ovariectomy

oops ['(w)u̇(ə)ps] -interj

  1. used typically to express mild apology, surprise, or dismay

Oort cloud ['ȯrt-] -n

  1. a spherical shell of cometary bodies believed to surround the sun far beyond the orbit of Pluto and from which some are dislodged when perturbed (as by a passing star) to fall toward the sun

oo·spore ['ō-ə-,spȯr] -n

  1. a spore (as of a fungus) produced by heterogamous fertilization

oo·the·ca [,ō-ə-'thē-kə] -n, adj

  1. a firm-walled and distinctive egg case (as of a cockroach)

oo·tid ['ō-ə-,tid] -n

  1. an egg cell after meiosis

ooze ['üz] -n

  1. a soft deposit (as of mud, slime, or shells) on the bottom of a body of water
  2. a piece of soft wet plastic ground
  3. to pass or flow slowly through or as if through small openings or interstices
  4. to move slowly or imperceptibly
    • the crowd began to ooze forward -- Bruce Marshall
  5. to exude moisture
  6. to exude something often in a faintly repellent manner
    • ooze with sympathy
  7. to emit slowly
  8. exude
    • ooze confidence
  9. a decoction of vegetable material used for tanning leather
  10. the act of oozing
  11. something that oozes

oozy ['ü-zē] -adj

  1. containing or composed of ooze : resembling ooze
  2. exuding moisture : slimy