o'clock

American  

[uh-klok] / əˈklɒk /

adverb

1. of, by, or according to the clock (used in specifying the hour of the day).

   It is now 4 o'clock.

2. 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.

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o'clock British  

/ əˈklɒk /

adverb

1. used after a number from one to twelve to indicate the hour of the day or night

2. 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

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Etymology

Origin of o'clock

First recorded in 1710–20; from o', a reduced form of of; see o' + clock ¹ ( def. )

Example Sentences

The stock was halted three times External link during the 10 o’clock hour on Tuesday.

From Barron's • Apr. 21, 2026

"The guests were all saying they were going to eat theirs at nine o'clock," Tracy said.

From BBC • Apr. 15, 2026

"One of the guys had queued from three o'clock in the morning," noted Scott, even though the store does not open until 10 am on Saturday.

From Barron's • Apr. 13, 2026

I love this house at 10 o’clock because of the cantilever and the shadows.

From Los Angeles Times • Apr. 13, 2026

They didn’t even need to be at the park until nine o’clock.

From "The Missing Mitt (The Hardy Boys: Secret Files, #2)" by Franklin W. Dixon