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; o' + clock ¹ ( def. )

Example Sentences

"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

Nothing they have compares to what my parents built on very little time together — simple pleasures and the freedom to be home at 5 o’clock.

From MarketWatch • Mar. 5, 2026

Shepherd said the post-mortem examination finding a piece of apple in Kirsty's small bowel, which "fits very well indeed with Kirsty dying between three and four o'clock in the morning".

From BBC • Feb. 7, 2026

"When I was going to school, I'd be doing my hair and makeup at like three o'clock in the morning, put music on, like literally had no concept of time."

From BBC • Feb. 6, 2026

The coat and outerwear at six o’clock in the morning.

From "The Brightwood Code" by Monica Hesse