What's the origin of the word "OK" ?

Answer 1

About the history of O.K.: Allen Walker Read did definitively
establish the source of O.K. as Old Kinderhook, from the campaign
of Martin Van Buren; but then his arch-enemy, a dictionary editor,
came up with an attestation that pre-dated the campaign. Read
then definitively established the source as "oll korrect", with
an attestation a few months earlier in the same year as the
arch-enemy's -- March, 1839. Read discusses the debate with
some passion in a New Yorker profile of Sept. 4, 1989. He also
discusses the matter briefly in his LACUS presidential address,
LACUS 14:5-17 (1988). He strongly disapproves of other suggestions,
including those from African language(s) and/or Native American
language(s). But if -- as he claims -- his 1839 attestation of
O.K. is the earliest, his oll korrect etymology would be hard to
impeach. (Both the odd spelling of the phrase and the abbreviation
to O.K., not to mention the meaning, are accounted for convincingly
in the context of the times -- apparently newspapers were full of
such cute-isms. The same can't be said of the Old Kinderhook
etymology.)