Definitions for O

This page provides all possible meanings and translations of the word O

Random House Webster's College Dictionary

O, o(n.)(pl.)O's; Os, o's; os; oes.

  1. the 15th letter of the English alphabet, a vowel.

  2. any spoken sound represented by this letter.

  3. something shaped like anO.

  4. a written or printed representation of the letter O or


O(interj.; n.)(pl.)O's.

  1. (interj.)(used before a name in direct address, esp. in solemn or poetic language, to lend earnestness to an appeal):

    Hear, O Israel!

  2. (used as an expression of surprise, pain, annoyance, longing, gladness, etc.)

  3. (n.)the exclamation “O.”

Origin of O:

1125–75; ME < OF < L ō


  1. Old.

  2. Gram. object.

    Category: Grammar


  1. the 15th in order or in a series.

  2. the Arabic numeral; zero; cipher.

  3. a major blood group.

    Category: Physiology

    Ref: Compare ABO system.

  4. oxygen.

    Category: Chemistry

* Symbol..


  1. of:

    o'clock; will-o'-the-wisp.

  2. Chiefly Dial. on.

Origin of o':

ME; by shortening.


  1. a prefix meaning “descendant,” in Irish family names:

    O'Brien; O'Connor.

    Category: Affix

Origin of O':

repr. Ir ó descendant, OIr au


  1. ortho-.

    Category: Chemistry, Affix


  1. var. of ob- before

    m: omission.

    Category: Affix


  1. var. of oo- :


    Category: Affix


  1. the typical ending of the first element of compounds of Greek origin, used regularly in forming new compounds with elements of Greek origin and often used in English as a connective irrespective of etymology: Franco-Italian; geography; seriocomic; speedometer.

    Category: Affix

    Ref: Compare -i-. 8

Origin of -o-:

ME (< OF) < L < Gk


  1. a suffix occurring as the final element in informal shortenings of nouns (ammo; combo; promo); -o also forms nouns, usu. derogatory, for persons or things exemplifying or associated with that specified by the base noun or adjective (pinko; weirdo; wino).

    Category: Affix

  2. a suffix occurring in informal noun or adjective derivatives, usu. grammatically isolated, as in address:

    kiddo; neato; righto.

    Category: Affix


  1. pint.

    Category: Weights and Measures

  2. October.

  3. Ohio.

Origin of O.:

< L octārius


  1. ocean.

  2. pint.

    Category: Weights and Measures

  3. octavo.

  4. off.

  5. old.

  6. only.

  7. order.

  8. out.

    Category: Sport

Origin of o.:

< L octārius

Princeton's WordNet

  1. oxygen, O, atomic number 8(noun)

    a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust

  2. O, o(noun)

    the 15th letter of the Roman alphabet

  3. O, type O, group O(noun)

    the blood group whose red cells carry neither the A nor B antigens

    "people with type O blood are universal donors"


  1. o(Noun)

    A zero .

  2. o(Interjection)

    The English vocative particle, used before a pronoun or the name of a person or persons to mark direct address.

  3. o(Interjection)


  4. o(Interjection)

    Object, see SVO

  5. o


  6. O(Noun)

    A blood type that lacks A or B antigens and may only receive transfusions of similar type O blood, but may donate to all (neglecting Rh factor). Synonym: universal donor.

  7. O(Noun)

    American Library Association

  8. O

    Someone associated with Leyton Orient Football Club, as a player, coach, supporter etc.

  9. O(Prefix)

    descendant of; used to form Irish patronymic surnames.

Webster Dictionary

  1. O

    o, the fifteenth letter of the English alphabet, derives its form, value, and name from the Greek O, through the Latin. The letter came into the Greek from the Ph/nician, which possibly derived it ultimately from the Egyptian. Etymologically, the letter o is most closely related to a, e, and u; as in E. bone, AS. ban; E. stone, AS. stan; E. broke, AS. brecan to break; E. bore, AS. beran to bear; E. dove, AS. d/fe; E. toft, tuft; tone, tune; number, F. nombre

  2. O

    among the ancients, O was a mark of triple time, from the notion that the ternary, or number 3, is the most perfect of numbers, and properly expressed by a circle, the most perfect figure

  3. O(noun)

    the letter O, or its sound

  4. O(noun)

    something shaped like the letter O; a circle or oval

  5. O(noun)

    a cipher; zero

  6. O(adj)


  7. O

    an exclamation used in calling or directly addressing a person or personified object; also, as an emotional or impassioned exclamation expressing pain, grief, surprise, desire, fear, etc


  1. O

    O is the fifteenth letter and a vowel in the ISO basic Latin alphabet.

Translations for O

Kernerman English Multilingual Dictionary


an expression used when speaking to a person, thing etc.

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