O
noun
the fifteenth letter of the English alphabet, a vowel.
Showing results for O.
Search instead for
e-o-.
Jump To:
-
O
-
o'
-
O'
O'a prefix meaning “descendant,” in Irish family names.
-
o-
o-an abridgment of ortho-.
-
-o
-oa 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 ).
-
o.
o.abbreviationpint.
-
-o-
-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.
-
O.
O.abbreviation(in prescriptions) a pint.
-
o
onounthe 15th letter and fourth vowel of the modern English alphabet
-
O'-
O'-prefix(in surnames of Irish Gaelic origin) descendant of
O
1 American
[oh]
/ oʊ /
Or
o
noun
-
O's,
plural
-
Os,
plural
-
o's,
plural
-
os,
plural
-
oes
plural
-
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.
O
2
American
[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
-
O's
plural
O
3
American
O
4
American
Symbol.
-
the fifteenth in order or in a series.
-
the Arabic cipher; zero.
-
(sometimes lowercase) the medieval Roman numeral for 11.
-
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.
-
Chemistry. oxygen.
-
Logic. particular negative.
o'
5
American
[uh, oh]
/ ə, oʊ /
O'
6
American
o-
7
American
Chemistry.
o-
8
American
o-
9
American
-o
10
American
-
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.
o.
11
American
abbreviation
o.
12
American
abbreviation
-
octavo.
-
off.
-
old.
-
only.
-
order.
-
Baseball. out; outs.
-o-
13
American
O.
14
American
abbreviation
O.
15
American
abbreviation
-
Ocean.
-
octavo.
-
October.
-
Ohio.
-
Old.
-
Ontario.
-
Oregon.
O
1
British
symbol
-
chem oxygen
-
a human blood type of the ABO group See universal donor
-
logic a particular negative categorial proposition, such as some men are not married: often symbolized as SoP Compare A E I 2
abbreviation
o
2
British
/ əʊ /
noun
-
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
O
3
British
/ əʊ /
interjection
-
a variant spelling of oh
-
an exclamation introducing an invocation, entreaty, wish, etc
O God!
O for the wings of a dove!
O'-
4
British
prefix
-o
5
British
suffix
-o-
6
British
o-
7
British
prefix
o'
8
British
/ ə /
preposition
Other Word Forms
Noun Inflected Forms
Etymology
Origin of O2
First recorded in 1125–75; Middle English, from Old French, from Latin ō
Origin of o'5
From Middle English; by shortening
Origin of O'6
Representing Irish ó descendant, Old Irish au
Origin of -o10
Perhaps originally the interjection O, appended to words as in -o def. 2; as a derivational suffix reinforced by clipped forms of words with -o- as a linking element (e.g., photo, stereo ), by Rom nouns ending in o, and by personal nouns such as bimbo and bozo, of obscure origin
Origin of o.11
From the Latin word octārius
Origin of -o-13
Middle English (< Old French ) < Latin < Greek
Origin of O.14
From the Latin word octārius
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Dr Labhrás O Murchú from CCÉ said the event was "unprecedented".
From BBC ● Aug. 10, 2026
Up until the Big O, I’ve lived by that rule.
From The Wall Street Journal ● Aug. 7, 2026
Test your knowledge of the English language: How many words can you create with the letters P, Y, C, R, O, and T?
From Slate ● Jul. 20, 2026
The exhibition "Hkeeli ya Jnoub", or "Tell me, O South", features pictures and videos preserving the memory of southern Lebanon at the capital's Beit Beirut museum.
From Barron's ● Jul. 19, 2026
"And lastly, O my resourceful son," said the Tisroc, "you have made clear how all this might give you the barbarian woman, but not how it helps me to the overthrowing of Narnia."
From "The Horse and His Boy" by C.S. Lewis
Velella velella, commonly known as by-the-wind sailors and closely related to the Portuguese man o' war, have been spotted on St Bees beach in recent weeks.
From BBC ● Jul. 30, 2026
“Coffee badging”—going to the office just long enough to show your face and grab a cup o’ joe—was a popular workaround.
From The Wall Street Journal ● Dec. 30, 2025
I was raised about two blocks from where you lived at the time, near Tail o’ the Pup.
From Los Angeles Times ● Jan. 22, 2025
Any way you slice it, this week’s Slate News Quiz is a piece o’ fun.
From Slate ● Nov. 1, 2024
“That Committee’s in Lucius Malfoy’s pocket. I’m jus’ gonna make sure the rest o’ Beaky’s time is the happiest he’s ever had.
From "Harry Potter And The Prisoner Of Azkaban" by J.K. Rowling
June O' Sullivan, who runs a chain of 42 London Early Years Foundation nurseries, said she was yet to see evidence of AI benefits in early years.
From BBC ● Mar. 12, 2026
Former basketball player Shaquille O’ Neal is also a high-profile investor.
From MarketWatch ● Nov. 19, 2025
But Heart O’ the Hills confirmed that its camp director, Jane Ragsdale, is one of the flood’s victims .
From Salon ● Jul. 7, 2025
Girls summer camp Heart O’ the Hills is just a mile north of Camp Mystic.
From Salon ● Jul. 7, 2025
After a single trip to the supermarket, the refrigerator and the cupboards fill with familiar labels: Skippy, Hood, Bumble Bee, Land O’ Lakes.
From "The Namesake" by Jhumpa Lahiri
At week's end a Russian delegation got the signatures of the leaders of Kazakhstan on a similar agreement-to-try-t o- agree.
From Time Magazine Archive
The soft, long-drawn "o- ohs!" that came to his ears were full of a music that made him impervious to pain.
From Green Fancy by George Barr McCutcheon
Phenol-2,4-disulphonic acid is prepared from o- or p-phenolsulphonic acid, whereas phenol-2,4,6-trisulphonic acid is prepared directly from phenol by heating with concentrated sulphuric acid in presence of phosphorus pentoxide.
From Synthetic Tannins by Georg Grasser
Similarly, condensation of different samples of crude cresol containing varying quantities of o-, m-, and p-cresol did not yield end-products sufficiently different to justify describing them in detail.
From Synthetic Tannins by Georg Grasser
It is hence possible to employ crude cresol, which contains varying quantities of the o-, m-, and p-compounds, in the manufacture of these tanning matters.
From Synthetic Tannins by Georg Grasser
Usually words ending in "-o" are masculine and those ending in "-a" are feminine, but there are many common words that break those gender rules, like "la mano," the word for "hand."
From Salon ● Sep. 26, 2022
I don't think the "-e" should eliminate the existing "-o" and the "-a."
From Salon ● Sep. 26, 2022
The -o suffix traces back to old comic strip characters with names like Knocko and Groucho.
From Slate ● Mar. 31, 2020
Knocko, Peddlo, Henpecko, and the rest became so popular that the -o suffix soon spread to words up and down the English language.
From Slate ● Mar. 31, 2020
I knew perfectly well why, but I didn’t know how -o put it.
From "Boy: Tales of a Childhood" by Roald Dahl
The P. o. wallikeri and the P. o. curtisi chromosomes were aligned against each other, as were the P. malariae and P. malariae-like chromosomes.
From Nature ● Jan. 24, 2017
The P. malariae-like and P. o. wallikeri genomes were both annotated using the Companion tool42.
From Nature ● Jan. 24, 2017
Reality is that you are giving up your family time by doing the o. t. when they need you at work.
From Time ● May 3, 2013
“If you dey come give am ticket to leave this here country, I will disappear o. I will not even stop home for pick my bag.”
From Washington Post
“Yes o. Are you the person that will marry me? Meanwhile I told Don I am going out with you, so make sure you don’t go anywhere that he might go.”
From "Americanah" by Chimamanda Ngozi Adichie
Thus masc. -o- stems show palatal modification, e.g. corn, “horn,” plur. cyrn < *kornī; the plural ending of -u- stems, O. Gaulish -oves, gives O.W. -ou, Mid.
From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" by Various
On Saturday, we watched Bishop John O. Barres lay hands on Dillon’s head to confer the sacrament of the priesthood on him.
From The Wall Street Journal ● Jun. 22, 2026
News of diGenova’s appointment comes on the heels of a prosecutor withdrawing from the case, apparently due to doubts she had about prosecuting former CIA director John O. Brennan.
From Salon ● Apr. 21, 2026
Mr. Yagoda is the author of the novel “Alias O. Henry.”
From The Wall Street Journal ● Apr. 17, 2026
Corona Centennial upset Corona 5-2 on Monday behind a complete game and 10 strikeouts from sophomore pitcher Christian De La O. Michael Nonis had three hits.
From Los Angeles Times ● Apr. 13, 2026
O. B. Dickerson spit in the gravel, swung around, and followed them, his big boots grinding gravel.
From "A Long Way from Chicago" by Richard Peck
My eyes watered as the camera panned over his arm-in-arm players as they shouted the line, “Think, o beloved homeland! That heaven/gave you a soldier in each son.”
From Los Angeles Times ● Jun. 25, 2026
Similarly, in June 2023, Iwan, called on protesters to stop using Yma o Hyd in opposition to housing asylum seekers at the Stradey Park Hotel in Carmarthenshire.
From BBC ● Feb. 1, 2026
Berkshire has the wherewithal of a huge stock buyback given that it’s sitting on o ver $350 billion of cash.
From Barron's ● Jan. 20, 2026
Mr. Brownlee’s tenor proved rock-solid in Arturo’s demanding music, from his exquisitely relaxed, almost languid opening aria, “A te, o cara,” to some punishing high Fs.
From The Wall Street Journal ● Jan. 2, 2026
G is pronounced hard before a, o, u, and soft like j before e, i, y, æ, œ: as gusto, in which g is pronounced as in August; gero, pronounced je'ro.
From New Word-Analysis by William Swinton
While some winning coaches were making their names with toughness that bordered on abuse, he urged Close to see her teams as human beings first, not X’s and O’s.
From The Wall Street Journal ● Apr. 6, 2026
Other experts, including the paediatric pathologist, said that Dr Aiton's observation of hyper-inflated lungs would not explain Baby O's liver injuries.
From BBC ● Aug. 11, 2025
Which raises the obvious question - if the prosecution were wrong about Baby O's liver injuries, then why did he die?
From BBC ● Aug. 11, 2025
The X’s and O’s won’t matter if Ayton doesn’t show up to play every night, however.
From Los Angeles Times ● Jul. 3, 2025
Finally de la O’s dad landed a full-time job in a meat-packing factory in Saint Paul, Minnesota.
From "Boots on the Ground: America's War in Vietnam" by Elizabeth Partridge
"The Dutch experience in my opinion offers a warning for Canada," Os cautioned.
From BBC ● May 15, 2026
Since then, Os has come to rule the Latin pop scene in Mexico, boasting multiple sold-out tours of the country.
From Los Angeles Times ● Mar. 20, 2026
Os would soon tour the U.S. for the first time, and at the 2023 Latin Grammy Awards, “K23” was nominated in the category of long form music video.
From Los Angeles Times ● Mar. 20, 2026
“It’s very beautiful to know that you have a partner that knows what you go through and that can give you advice from his experiences as well,” Os says.
From Los Angeles Times ● Mar. 20, 2026
Black and red letters and crazy eyes inside the Os.
From "Brown Girl Dreaming" by Jacqueline Woodson
They eventually named their institute for an online trend that had slime enthusiasts replacing the vowels in their name with double o’s, so Kira would become “Kooroo” and slime becomes “Sloomoo.”
From Washington Post ● Jun. 30, 2022
Like other Romance languages, Spanish divides most endings of nouns into masculine o’s or feminine a’s.
From Washington Times ● Dec. 12, 2021
Mathematics said that any concept could be conveyed in such a binary code as long as the sequence of i’s and o’s was long enough.
From Forbes ● Sep. 2, 2014
The promotion is “a really great fit with an Americana brand,” Mr. Addicks said, particularly because “Cheerios have always been about nurturing; they’re the little o’s that go with you through life.”
From New York Times ● Nov. 9, 2011
Since the censors’ Greek was even worse than Milton’s, they often made mistakes, lopping off endearments, x’s and o’s.
From "Middlesex: A Novel" by Jeffrey Eugenides
Dreyfus pleased his friends no better than his :oes: he irked them by not becoming a "Dreyfusard."
From Time Magazine Archive
The poet "mouthing out his hollow oes and aes" is, we are told, a good description of Tennyson's tone and manner of reading.
From The Early Poems of Alfred Lord Tennyson by John Churton Collins
I was taking a lesson in Welsh pronunciation some time ago, and uttered the phrase "yn oes oesodd"—from ages to ages.
From Far Off Things by Arthur Machen
Ir wyfi yn meddwl nad oes neb a ryfygei gymmeryd y fath orchest arno.
From Some Specimens of the Poetry of the Ancient Welsh Bards by Evan Evans
However thick-skinned a man may be, and protected over all by the oes triplex of self-sufficiency, he cannot escape being wounded by furious and incessant attacks.
From The Atlantic Monthly, Volume 04, No. 21, July, 1859 by Various
A new Longevity Preparedness Index from John Hancock and MIT AgeLab os based on a survey of over 1,300 adults and focused on eight areas such as finance, home, health and community.
From MarketWatch ● Dec. 12, 2025
She first broke through with 2016’s “Remonta,” an album she recorded with her former band Liniker e os Caramelows.
From Los Angeles Times ● Oct. 8, 2025
Ambos os programas são “fundamentais para entender a expansão agrícola no Brasil e as emissões de carbono do desmatamento na Amazônia,” diz Douglas Morton, especialista em sensoriamento remoto do Goddard Space Flight Center da NASA.
From Science Magazine ● May 26, 2022
Hours later, Kelly posts bail and os released from jail in Chicago.
From Seattle Times ● Aug. 18, 2021
Newton disliked infinitesimals, the little os in his fluxion equations that sometimes acted like zeros and sometimes like nonzero numbers.
From "Zero: The Biography of a Dangerous Idea" by Charles Seife
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
