We say it countless times everyday, but have you ever thought what "OK" actually stands for? It was even one of the first words spoken on the moon.

Okay is a colloquial English word denoting approval, acceptance, assent, or acknowledgment. This is most likely short for “Oll Korrect,” a jokey misspelling of “All Correct” that needs a little historical context to make sense.

There have been numerous attempts to explain the emergence of this expression, which seems to have swept into popular use in the US (United States) during the mid-19th century. Most of them are pure speculation.

In his 2001 book OK: The Improbable Story of America's Greatest Word, Allan Metcalf deems OK "the most frequently spoken (or typed) word on the planet - used more often than 'Coke' or an infant's 'ma'".

Is it correct to write "OK" or is it "Okay"?

If you write "okay", you’d be wrong. It’s more correct to write OK because it is actually an acronym.