o'clock
Americanadverb
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of, by, or according to the clock (used in specifying the hour of the day).
It is now 4 o'clock.
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according to a method for indicating relative position whereby a plane in space is considered to be numbered as a clock's face, with 12 o'clock considered as directly ahead in horizontal position or straight up in vertical position.
adverb
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used after a number from one to twelve to indicate the hour of the day or night
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used after a number to indicate direction or position relative to the observer, twelve o'clock being directly ahead or overhead and other positions being obtained by comparisons with a clock face
Etymology
Origin of o'clock
First recorded in 1710–20; from o', a reduced form of of; see o' + clock 1 ( def. )
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.
Shortly after 10 o'clock this morning Andy Burnham finally confirmed what had been obvious for days - that he would stand to be the next Labour leader and therefore the UK's next prime minister.
From BBC • Jun. 22, 2026
Another moment that I really like in the show is Odessa’s character, she wants to change a dinner reservation to five people at 8 o’clock.
From Los Angeles Times • Jun. 18, 2026
"When I was going home at 11 o'clock that night the bins were all full."
From BBC • May 27, 2026
"I fail to understand why anybody... is serving people at five or six o’clock in the morning," he told the paper.
From Barron's • May 6, 2026
At one o’clock in the morning, a square-jawed private arrived at the barracks, roused Captain Babushkinov, and informed him that the furious general had challenged him to a duel.
From "The Long-Lost Home" by Maryrose Wood
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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.