O, o
[ oh ]
/ oʊ /
noun, plural O's or Os; o's or os or oes.
the fifteenth letter of the English alphabet, a vowel.
any spoken sound represented by the letter O or o, as in box, note, short, or love.
something having the shape of an O.
a written or printed representation of the letter O or o.
a device, as a printer's type, for reproducing the letter O or o.
Definition for o (2 of 16)
O
[ oh ]
/ oʊ /
interjection
(used before a name in direct address, especially in solemn or poetic language, to lend earnestness to an appeal): Hear, O Israel!
(used as an expression of surprise, pain, annoyance, longing, gladness, etc.)
noun, plural O's.
the exclamation “O.”
Origin of O
1125–75; Middle English < Old French < Latin
ō
Definition for o (3 of 16)
Definition for o (4 of 16)
O
Symbol.
the fifteenth in order or in a series.
the Arabic cipher; zero.
Physiology.
a major blood group, usually enabling a person whose blood is of this type to donate blood to persons of group O, A, B, or AB and to receive blood from persons of group O.
Compare ABO system.
Chemistry.
oxygen.
Logic.
particular negative.
Definition for o (5 of 16)
o'
[ uh, oh ]
/ ə, oʊ /
preposition
an abbreviated form of of, as in o'clock or will-o'-the-wisp.
an abbreviated form of on.
Origin of o'
Middle English; by shortening.
Definition for o (6 of 16)
O'
a prefix meaning “descendant,” in Irish family names: O'Brien; O'Connor.
Origin of O'
representing Irish
ó descendant, Old Irish
au
Definition for o (7 of 16)
Definition for o (8 of 16)
Definition for o (9 of 16)
Definition for o (10 of 16)
Origin of o.
1
From the Latin word
octārius
Definition for o (11 of 16)
Definition for o (12 of 16)
-o
a suffix occurring as the final element in informal shortenings of nouns (ammo; combo; condo; limo; promo); -o also forms nouns, usually derogatory, for persons or things exemplifying or associated with that specified by the base noun or adjective (cheapo; pinko; sicko; weirdo; wino).
a suffix occurring in colloquial noun or adjective derivatives, usually grammatically isolated, as in address: cheerio; kiddo; neato; righto.
Definition for o (13 of 16)
-o-
the typical ending of the first element of compounds of Greek origin (as -i- is, in compounds of Latin 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.
Compare
-i-.
Origin of -o-
Middle English (< Old French) < Latin < Greek
Definition for o (14 of 16)
O.
1
(in prescriptions) a pint.
Origin of O.
1
From the Latin word
octārius
Definition for o (15 of 16)
O.
2
Definition for o (16 of 16)
omicron
[ om-i-kron, oh-mi- ]
/ ˈɒm ɪˌkrɒn, ˈoʊ mɪ- /
noun
the 15th letter of the Greek alphabet (O, o).
the vowel sound represented by this letter.
Origin of omicron
Example sentences from the Web for o
British Dictionary definitions for o (1 of 8)
o
O
/ (əʊ) /
noun plural o's, O's or Os
the 15th letter and fourth vowel of the modern English alphabet
any of several speech sounds represented by this letter, in English as in code, pot, cow, move, or form
another name for nought
British Dictionary definitions for o (2 of 8)
O
1
symbol for
chem
oxygen
a human blood type of the ABO group
See universal donor
abbreviation for
Australian slang
offence
Word Origin for O
(for sense 3) from Latin (
neg)
o I deny
British Dictionary definitions for o (3 of 8)
O
2
/ (əʊ) /
interjection
a variant spelling of oh
an exclamation introducing an invocation, entreaty, wish, etc
O God!; O for the wings of a dove!
British Dictionary definitions for o (4 of 8)
British Dictionary definitions for o (5 of 8)
British Dictionary definitions for o (6 of 8)
-o
suffix
forming informal and slang variants and abbreviations, esp of nouns
wino; lie doggo; Jacko
Word Origin for -o
probably special use of
oh
British Dictionary definitions for o (7 of 8)
omicron
/ (əʊˈmaɪkrɒn, ˈɒmɪkrɒn) /
noun
the 15th letter in the Greek alphabet (Ο, ο), a short vowel, transliterated as o
Word Origin for omicron
from Greek
ō mikron small o; see
micro-,
omega
British Dictionary definitions for o (8 of 8)
-o-
connective vowel
used to connect elements in a compound word
chromosome; filmography Compare -i-
Word Origin for -o-
from Greek, stem vowel of many nouns and adjectives in combination
Medical definitions for o (1 of 3)
o-
abbr.
ortho- (often italic)
Medical definitions for o (2 of 3)
-o-
Used as a connective to join word elements:acidophilic.
Medical definitions for o (3 of 3)
omicron
[ ŏm′ĭ-krŏn′, ō′mĭ- ]
n.
The 15th letter of the Greek alphabet.
Scientific definitions for o (1 of 2)
O
The symbol for oxygen.
Scientific definitions for o (2 of 2)
oxygen
[ ŏk′sĭ-jən ]
O
A nonmetallic element that exists in its free form as a colorless, odorless gas and makes up about 21 percent of the Earth's atmosphere. It is the most abundant element in the Earth's crust and occurs in many compounds, including water, carbon dioxide, and iron ore. Oxygen combines with most elements, is required for combustion, and is essential for life in most organisms. Atomic number 8; atomic weight 15.9994; melting point -218.8°C; boiling point -182.9°C; gas density at 0°C 1.429 grams per liter; valence 2. See Periodic Table.
Word History
In 1786, the French chemist Antoine Lavoisier coined a term for the element oxygen (oxygène in French). He used Greek words for the coinage: oxy- means sharp, and -gen means producing. Oxygen was called the sharp-producing element because it was thought to be essential for making acids. Lavoisier also coined the name of the element hydrogen, the water-producing element, in 1788. Soon after, in 1791, another French chemist, J. A. Chaptal, introduced the word nitrogen, the niter-producing element, referring to its discovery from an analysis of nitric acid.