The origins of 'o'clock' revealed: What the 'O' really stands for

The phrase "o'clock" is a ubiquitous part of the English language, used daily by millions to express time. However, the meaning behind the "o" in "o'clock" has recently sparked curiosity and discussion online, leading many to uncover its true origin.

A question posed by a user on the social media platform Threads asked, "What’s the meaning of ‘O’ in o’clock?" The query drew a wide range of responses, with users speculating that the "o" might stand for "zero," "Omega," or even "oida" (a Viennese term for "old person"). However, the correct answer is more historically rooted.

The "o" in "o'clock" is actually a contraction of the phrase "of the clock." Historically, when clocks were a relatively new invention, people would specify the time by saying it was "3 of the clock" to distinguish it from other ways of telling time, such as using a sundial. Over time, this phrase was shortened to "3 o'clock," with the "of the" becoming simply "o'."

This explanation aligns with the authoritative view from sources like the Britannica Dictionary, which states that an apostrophe is used in "o'clock" because it is a contraction of "of the clock."