O
noun
the fifteenth letter of the English alphabet, a vowel.
Showing results for O.
Search instead for
f-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:
It offers a sports-themed way of approaching the topic, called GOALS, representing G: get ready; O: open the conversation; A: ask the question; L: listen and respond and S: support and signpost.
From BBC ● Sep. 9, 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
A temporary pebble O that just keeps on getting wrecked.
From "Maybe He Just Likes You" by Barbara Dee
“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
Amelie McCann said Julia Wandelt had told her she had memories of playing Ring a Ring o' Roses with her and feeding her brother Sean.
From BBC ● Oct. 9, 2025
These sea snails are also voracious predators themselves and feast upon free-floating hydrozoan such as Velella velella and Portuguese man o’ war.
From Los Angeles Times ● Jul. 23, 2025
Any way you slice it, this week’s Slate News Quiz is a piece o’ fun.
From Slate ● Nov. 1, 2024
“Arthur’s done a bit o’ tinkerin’,” said Hagrid, quite oblivious to Harry’s discomfort.
From "Harry Potter and the Deathly Hallows" by J.K. Rowling
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
Sir Ringo can be heard narrating in the new footage alongside a slightly different bespoke musical arrangement by longtime series composer Mike O' Donnell.
From BBC ● May 9, 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
In the absence of free sulphuric acid the conversion of o- into p-phenolsulphonic acid is brought about by heating the aqueous solution.
From Synthetic Tannins by Georg Grasser
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
Of the three isomeric xylenes o- and m-xylene dissolve in concentrated, p-xylene in fuming sulphuric acid only.
From Synthetic Tannins by Georg Grasser
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
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
Using a new reference genome for P. malariae and a manually curated draft P. o. curtisi genome, we are now able to accurately place these species within the Plasmodium phylogeny.
From Nature ● Jan. 24, 2017
As a Gene Ontology database, the predicted Gene Ontology terms from the P. falciparum 3D7 genes orthologous to the P. malariae and P. o. curtisi genes included in the analysis were used.
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
Then she added, “Sorry o. I did not mean that your boyfriend is a criminal. I was just asking.”
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
Thankfully, Curry did not allow any eerie rumors to deter him from securing the home, which was originally built in 1922, having been designed by acclaimed architect Stiles O. Clements.
From MarketWatch ● Aug. 31, 2026
The elegantly presented “An Exquisite Eye: Introducing the Aso O. Tavitian Collection,” at the Clark, offers a preview with 150 works by artists from different countries, deploying different mediums, united by consistent excellence.
From The Wall Street Journal ● Aug. 29, 2026
The Senate opened debate this week on the late South Carolina senator’s legacy legislation—the Lindsey O. Graham Sanctioning Russia and Iran Act—by an overwhelming 86–12 vote.
From Slate ● Aug. 1, 2026
And if he’s going to be a senator, he says, he needs to lock down a Jackie O. – not a Marilyn.
From Salon ● Jul. 6, 2026
Men and boys who were already in the fields irrigating looked up, laughing, and the women of Milagro watched O. J. come and go from their front doorsteps or parlor windows.
From "The Milagro Beanfield War" by John Nichols
Agricultural scientist professor Grant Edwards, who is is the vice-chancellor of Te Whare Wanaka o Aoraki Lincoln University, a specialist institution in New Zealand, is also receiving a fellowship.
From BBC ● Sep. 14, 2026
Allow me to sing, o Muse, of a recent dinner conversation about “The Odyssey.”
From Salon ● Aug. 2, 2026
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
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
But I feel that in order to do our duty to the party, we gotta—” o o o .. which is why I ask it.
From "Feed" by M.T. Anderson
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
Does the olfactory exhilaration also enhance play-calling, amplifying one’s grasp of X’s and O’s?
From Los Angeles Times ● Jan. 12, 2026
The prosecution pathologist concluded that there was no evidence that a needle had pierced Baby O's liver while he was alive and the paediatric pathologist we spoke to agrees.
From BBC ● Aug. 11, 2025
Since that press conference, other experts working for Letby's defence team have put forward another theory for Baby O's death.
From BBC ● Aug. 11, 2025
“I know Coach O's got to be talking to you about playing football, too,” he continued.
From "Tradition" by Brendan Kiely
"The Dutch experience in my opinion offers a warning for Canada," Os cautioned.
From BBC ● May 15, 2026
As a show of gratitude to the girls and the gays, Os transforms from “Belladona” to Primadonna in vogue-ready house bangers like “Slay,” “Problemática,” and “Boom In Your Face.”
From Los Angeles Times ● Mar. 20, 2026
Os had plenty of examples of powerful pop divas to draw inspiration from.
From Los Angeles Times ● Mar. 20, 2026
Last year, Os also pulled a page from Taylor Swift’s playbook by releasing the concert film “Kenia Os: La OG” in theaters in both the U.S. and Mexico.
From Los Angeles Times ● Mar. 20, 2026
“Brother, that water felt good,” she said, drawing out the word “good” so it sounded like it had about fifteen Os in it.
From "The Glass Castle" by Jeannette Walls
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
Twitter’s closed captioning wrote it out twice, with each ¡Gol! featuring 27 o’s.
From Slate ● Jun. 17, 2018
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
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
And from the shadow one by one Pick up the playful oes of sun?
From The Poetical Works of Robert Bridges by Robert Bridges
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
Yr un peth a ellir ei ddywedyd am Daliesin Ben Beirdd, nid oes neb heddyw, hyd i gwn i, a fedr gyfieithu yn iawn un o’i Awdlau na’i Orchanau.
From Some Specimens of the Poetry of the Ancient Welsh Bards by Evan Evans
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
The os in his calculations were only intermediaries, crutches that vanished miraculously by the end of the computation.
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.
