What does O mean?

Definitions for O

This dictionary definitions page includes all the possible meanings, example usage and translations of the word O.

Princeton's WordNet

  1. oxygen, O, atomic number 8noun

    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, onoun

    the 15th letter of the Roman alphabet

  3. O, type O, group Onoun

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

    "people with type O blood are universal donors"


  1. onoun

    A zero .

  2. ointerjection

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

  3. ointerjection


  4. ointerjection

    Object, see SVO

  5. o


  6. Onoun

    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. Onoun

    American Library Association

  8. O

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

  9. Oprefix

    descendant of; used to form Irish patronymic surnames.

Samuel Johnson's Dictionary

  1. O

    O that we, who have resisted all the designs of his love, would now try to defeat that of his anger! Decay of Piety.

    O! were he present, that his eyes and hands
    Might see, and urge, the death which he commands. Dryd.

    Can this cockpit hold
    The vasty field of France? or may we cram
    Within this wooden O, the very casks
    That did affright the air at Agincourt? William Shakespeare.


  1. O

    O (named o, plural oes) is the 15th letter and the fourth vowel in the modern English alphabet and the ISO basic Latin alphabet.


  1. O

    The letter "O" is the fifteenth letter of the English alphabet, following "N" and preceding "P." It is a vowel and is commonly used as a graphical representation of certain sounds in spoken language.

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. Onoun

    the letter O, or its sound

  4. Onoun

    something shaped like the letter O; a circle or oval

  5. Onoun

    a cipher; zero

  6. Oadjective


  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

  8. Etymology: [See One.]


  1. O

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

Chambers 20th Century Dictionary

  1. O

    oh, ō, interj. an exclamation of wonder, pain, desire, fear, &c. The form oh is the more usual in prose.—O hone! Och hone! an Irish exclamation of lamentation. [A.S. .]

  2. O

    usually written o', an abbrev. for of and on.

Dictionary of Nautical Terms

  1. o

    The fourth class of rating on Lloyd's books for the comparative excellence of merchant ships. But insured vessels are rarely so low. (See A.) O! OR HO! An interjection commanding attention or possibly the cessation of any action.

Suggested Resources

  1. o

    The o symbol -- In this Symbols.com article you will learn about the meaning of the o symbol and its characteristic.

  2. o

    Song lyrics by o -- Explore a large variety of song lyrics performed by o on the Lyrics.com website.

Matched Categories

How to pronounce O?

How to say O in sign language?


  1. Chaldean Numerology

    The numerical value of O in Chaldean Numerology is: 7

  2. Pythagorean Numerology

    The numerical value of O in Pythagorean Numerology is: 6

Examples of O in a Sentence

  1. Bill Cosby:

    The entire mode of The Cosby Show can't proceed, o.J. completely trumps everything else that's been happening in the episode.

  2. Sir Walter Scott:

    O, what a tangled web we weave, When first we practice to deceive!

  3. Sir Thomas More:

    Why dost thou gaze upon the sky O that I were yon spangled sphere Then every star should be an eye, To wander o'er thy beauties here.

  4. An NCIS spokesman:

    The Naval Criminal Investigative Service (NCIS) is in receipt of an allegation that Mr. O'Neill may have revealed classified information to persons not authorized to receive such information, in response, NCIS has initiated an investigation to determine the merit of the allegations.

  5. Dante Alighieri:

    O human race born to fly upward, wherefore at a little wind dost thou fall.

Popularity rank by frequency of use


Translations for O

From our Multilingual Translation Dictionary

Get even more translations for O »


Find a translation for the O definition in other languages:

Select another language:

  • - Select -
  • 简体中文 (Chinese - Simplified)
  • 繁體中文 (Chinese - Traditional)
  • Español (Spanish)
  • Esperanto (Esperanto)
  • 日本語 (Japanese)
  • Português (Portuguese)
  • Deutsch (German)
  • العربية (Arabic)
  • Français (French)
  • Русский (Russian)
  • ಕನ್ನಡ (Kannada)
  • 한국어 (Korean)
  • עברית (Hebrew)
  • Gaeilge (Irish)
  • Українська (Ukrainian)
  • اردو (Urdu)
  • Magyar (Hungarian)
  • मानक हिन्दी (Hindi)
  • Indonesia (Indonesian)
  • Italiano (Italian)
  • தமிழ் (Tamil)
  • Türkçe (Turkish)
  • తెలుగు (Telugu)
  • ภาษาไทย (Thai)
  • Tiếng Việt (Vietnamese)
  • Čeština (Czech)
  • Polski (Polish)
  • Bahasa Indonesia (Indonesian)
  • Românește (Romanian)
  • Nederlands (Dutch)
  • Ελληνικά (Greek)
  • Latinum (Latin)
  • Svenska (Swedish)
  • Dansk (Danish)
  • Suomi (Finnish)
  • فارسی (Persian)
  • ייִדיש (Yiddish)
  • հայերեն (Armenian)
  • Norsk (Norwegian)
  • English (English)

Word of the Day

Would you like us to send you a FREE new word definition delivered to your inbox daily?

Please enter your email address:


Use the citation below to add this definition to your bibliography:


"O." Definitions.net. STANDS4 LLC, 2023. Web. 3 Oct. 2023. <https://www.definitions.net/definition/O>.

Discuss these O definitions with the community:


    Are we missing a good definition for O? Don't keep it to yourself...

    Image or illustration of


    Credit »

    Free, no signup required:

    Add to Chrome

    Get instant definitions for any word that hits you anywhere on the web!

    Free, no signup required:

    Add to Firefox

    Get instant definitions for any word that hits you anywhere on the web!

    Browse Definitions.net


    Are you a words master?

    relating to or concerned with a city or densely populated area
    • A. urban
    • B. whirring
    • C. profound
    • D. occasional

    Nearby & related entries:

    Alternative searches for O: