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.
"We had to stop at 10 o'clock in the morning."
From BBC ● Sep. 30, 2026
He’d go to bed probably at midnight, one o’clock, and he’s up taking the kids to school, he’s mountain biking, and he’s ready to roll.
From Los Angeles Times ● Aug. 13, 2026
“But we also like to deposit them back at their parents’ house at 7 o’clock, so we can be in bed to read at 8.”
From The Wall Street Journal ● Jul. 29, 2026
"You've got fans leaving at three o'clock in the morning or you're going the night before and having to pay for a hotel."
From BBC ● Jul. 24, 2026
By six o'clock the house was filled with delicious aromas.
From "Jeremy Thatcher, Dragon Hatcher" by Bruce Coville
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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.