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.

---

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

---

Etymology

Origin of o'clock

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

Example Sentences

“I fail to understand why anybody in airport bars is serving people at five or six o’clock in the morning,” he told British newspaper the Times.

From The Wall Street Journal • Jun. 5, 2026

Only one, located at 9 o’clock and close to the nipple, slightly concerned Margolies, even though it hadn’t changed in size or shape.

From The Wall Street Journal • May 4, 2026

"The street was quiet, as you would expect, at three o'clock in the morning."

From BBC • May 2, 2026

I could hear all the traffic in L.A. coming to my house at two o’clock when the pubs and the discos closed.

From Los Angeles Times • Apr. 30, 2026

Over the walkie-talkie, he heard a static-y version of Chip’s voice: “Oh, hello. Are you the person who reserved this conference room for three o’clock? The one who’s willing to talk?”

From "Found" by Margaret Peterson Haddix