OK, here's a great explainer on the origins of the word "OK"

Because of its ubiquity, the landscape is littered with proposed etymologies of the term "OK." This nice explainer clarifies the murky origins of one of the most widely spoken words in the world.

it actually dates back to an obscure language fad in the 1830s where people facetiously misspelled abbreviations.

Young Boston intellectuals in the early 1800s used a humorous code of abbreviated phrases, like "KC," or "knuff ced"; "KY," "know yuse"; and "OW," "oll wright." And while most of them eventually fell out of fashion, one abbreviation persisted: "OK," or "oll korrect."

All correct, a cousin of all right, was a common 19th-century affirmative that indicated everything was in order. Thanks to a series of lucky breaks, its jokey abbreviation, "OK" survived — and even ended up being (arguably) the first word spoken on the moon.

Why we say "OK" (YouTube / Vox)

Image: Horia Varlan