Where does the word OK come from?

The best-documented origin traces to a fad among educated young men in Boston around 1839 for humorous abbreviations of deliberately misspelled phrases. OK stood for oll korrect, a joke rendering of all correct, alongside similar coinages that did not survive. Its first known appearance in print is in the Boston Morning Post in March 1839. What rescued it from being a forgotten in-joke was the 1840 presidential campaign of Martin Van Buren, nicknamed Old Kinderhook after his New York hometown, whose supporters formed OK Clubs and used the initials as a slogan, giving the term national circulation and a second meaning at once.

Competing origin stories are numerous and mostly unsupported. Claims trace it to Choctaw okeh, to West African languages, to Greek ola kala, to a Scottish expression, to railway clerks, to shipping notations, and to a Civil War abbreviation for zero killed, which fails on chronology alone since the word predates the war by two decades. The linguist Allen Walker Read established the Boston origin through documentary research in the 1960s, and it remains the accepted account, though the Choctaw hypothesis has serious advocates and the possibility of parallel reinforcement is not dismissed outright.

The word's spread is the more remarkable part. OK travelled globally through the telegraph, where its brevity and distinctiveness were useful, then through American commerce, film, and computing, and it now functions in a very large number of languages with minimal adaptation. Its flexibility is unusual: it serves as agreement, acknowledgment, a quality assessment, a discourse marker opening a sentence, an adjective, a verb meaning to approve, and a noun. The spellings OK, okay, and O.K. all appear in edited prose, with style guides differing, and okeh survives as a rare variant.