OK, OK, OK, this is a fun, interesting video from Vox on that most recognisable of words, OK, which dates from 1839.
It’s not an abbreviation for a dockworker’s name (which is what I’d heard). It’s not from the Choctaw. But it does have an unexpected origin.
Also, “It affirms without evaluating,” which is part of why it endures.
OK, got it.