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1

o

noun, often capitalized often attributive \ˈō\

Simple Definition of o

  • : the 15th letter of the English alphabet

  • : the number zero

  • —used as a mark at the end of a letter, an e-mail, etc., to represent a hug

Source: Merriam-Webster's Learner's Dictionary

Full Definition of o

plural

o's

or

os

\ˈōz\
  1. 1 a :  the 15th letter of the English alphabet b :  a graphic representation of this letter c :  a speech counterpart of orthographic o

  2. 2 :  a graphic device for reproducing the letter o

  3. 3 :  one designated o especially as the 15th in order or class

  4. 4 :  something shaped like the letter O; especially :  zero

Examples of o in a sentence

  1. a word that starts with an o

  2. a word that starts with o



Before 12th Century

First Known Use of o

before 12th century

Other Alphabet Terms


2

o

abbreviation

Definition of o

  1. 1 ocean

  2. 2 ohm

  3. 3 old

  4. 4 order

  5. 5 over




1

O

Definition of O

  1. variant of oh




2

O

noun

Definition of O

  1. :  the one of the four ABO blood groups characterized by the absence of antigens designated by the letters A and B and by the presence of antibodies against these antigens



1929

First Known Use of o

1929


3

O

abbreviation

Definition of O

  1. 1 offense

  2. 2 Ohio

  3. 3 [New Latin octarius] pint




4

O

symbol

Definition of O

  1. oxygen




1

o-

combining form

Definition of o-

  1. :  egg <oology>; specifically :  ovum <oogonium>



Variants of o-

or

oo-

Origin and Etymology of o-

Greek ōi-, ōio-, from ōion — more at egg


2

o-

abbreviation

Definition of o-

  1. orth- or ortho-




-o-

Definition of -o-

  1. —used as a connective vowel originally to join word elements of Greek origin and now also to join word elements of Latin or other origin <speedometer> <elastomer>



Origin and Etymology of -o-

Greek, thematic vowel of many nouns and adjectives in combination


1

-o

noun suffix

Definition of -o

  1. :  one that is, has the qualities of, or is associated with <bucko>



Origin and Etymology of -o

perhaps from 1oh


2

-o

interjection suffix

Definition of -o

  1. —in interjections formed from other parts of speech <cheerio> <righto>



Origin and Etymology of -o

probably from 1oh



O Defined for Kids

o

noun , often cap \ˈō\

Definition of o for Students

plural

o's

or

os

\ˈōz\
  1. 1 :  the 15th letter of the English alphabet

  2. 2 :  zero 1




O

Definition of O for Students

  1. variant of oh




Medical Dictionary

noun \ˈō\

Medical Definition of O

  1. :  the one of the four ABO blood groups characterized by the absence of antigens designated by the letters A and B and by the presence of antibodies against these antigens




O

abbreviation

Medical Definition of O

  1. 1opening

  2. 2[Latin octarius] pint—used in writing prescriptions




O

symbol

Medical Definition of O

  1. oxygen




o-

abbreviation

Medical Definition of o-

  1. orth-; ortho-




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