People say it every day without thinking ― “two o’clock,” “six o’clock,” “eight o’clock sharp.” But what is the purpose of that little “o” and apostrophe? Is it short for something? Why do we only use it for certain times?
(If you’re a fan of “The Gilded Age” on HBO, you might even wonder ― does it have anything to do with the fan favorite character affectionately called “Clock Twink”?)
The origin of “o’clock,” however, goes back much further than the Gilded Age. It doesn’t stand for “hour,” and it’s not derived from some whimsical Irish surname, either.
“O’clock” is a shortened form of the phrases “of the clock” and “of clock,” which people began using to communicate the time after the invention of clocks. Saying it was five “of the clock” essentially meant five “according to the clock.”
“When mechanical clocks became more widespread in Europe around the 14th century, people needed a way to distinguish the hour shown on a clock from other ways of telling time, such as by the sun or church bells,” said Esteban Touma, a cultural and linguistic expert at the language-learning app Babbel. “If someone said ‘three,’ that could once have meant three hours after sunrise or simply a rough point in the day. Saying ‘three of the clock’ clarified that you meant the specific hour indicated on a mechanical clock face.”
