by Mark Israel
     [This is a fast-access FAQ excerpt.]

This one has generated *lots* of folklore.  The following list of
suggested origins and info comes from MEU2, from Eric Partridge's
Dictionary of Historical Slang (1972 edition, Penguin,
0-14-081046-X), and from Cecil Adams' More of the Straight Dope
(Ballantine, 1988, ISBN 0-345-34145-2).  Thanks to Jeremy Smith for
his help.  The abbreviations on cracker boxes, shipping crates,
cargoes of rum, et al., became synonymous with quality.

   "Oll korrect, popularized by Old Kinderhook" is what's given in
most up-to-date dictionaries.  The earliest known citation is from
the Boston Morning Post of 23 March 1839:  " [...] he of the
Journal, and his train-band, would have the 'contributions box,' et
ceteras, o.k. -- all correct -- and cause the corks to fly."  This
was a facetious suggestion by a Boston editor that a Providence
editor (the Journal mentioned was in Providence) sponsor a party.

American "O.K.", abbreviation of Obadiah Kelly, a shipping agent
American "O.K.", abbreviation of Old Keokuk, a Sac Indian chief
American "O.K.", contraction of "oll korrect".  This was the choice
   of a British judiciary committee that investigated the matter for
   a 1935 court case (MEU2), and was further documented by Columbia
   University professor Allen Walker Read in "The Evidence on
   'O.K.', Saturday Review of Literature, 19 July 1941.  A vogue
   for comically misspelled abbreviations began in Boston in the
   summer of 1838, and spread to New York and New Orleans in 1839.
   They used "K.G." for "know go", "K.Y." for "know yuse", "N.S."
   for "nuff said", and "O.K." for "oll korrect".
American "O.K.", abbreviation of Orrins-Kendall crackers
American "O.K.", abbreviation of Otto Kaiser, American industrialist
American "O.K. Club".  "O.K." gained national currency in 1840 as
   the slogan of the "O.K. club", a club of supporters of then
   President Martin Van Buren, in allusion to his nickname, "Old
   Kinderhook" -- Van Buren was born in the village of Kinderhook,
Choctaw (h)oke = "it is so"
English opposite of "K.O." ("knock out")
English "of Katmandu"
English "open key"
English "optical kleptomaniac"
English "our kind"
Ewe (West African)
Finnish oikea
French Aux Cayes, a place in Haiti noted for excellence of its rum
French aux quais, stencilled on Puerto Rican rum specially
   selected for export
German ordnungsgemaess kontrolliert "properly checked"
German letters of rank appended to signature of Oberkommandant
Greek olla kalla = "all good"
Latin omnia correcta = "all correct"
Mandingo (West African) = o ke "that's it", "all right"
Occitan oc = "yes" (Occitan or Langue d'Oc is so called because it
    uses oc where French uses oui.)
Scots och aye! "oh yes"
Tewa oh-ka(n) = "come here", "all right"
Wolof (West African) "waw kay" = "yes indeed".  Supported by Prof.
   J. Weisenfeld, professor of African and African-American religion
   at Columbia University.  It was shown by Dr Davis Dalby ("The
   Etymology of O.K.", The Times, 14 January 1971) that similar
   expressions were used very early in the 19th century by Negroes
   of Jamaica, Surinam, and South Carolina:  a Jamaican planter's
   diary of 1816 records a Negro as saying "Oh ki, massa, doctor no
   need be fright, we no want to hurt him."  The use of "kay" alone
   is recorded in the speech of black Americans as far back as 1776;
   significantly, the emergence of O.K. among white Americans dates
   from a period when refugees from southern slavery were arriving
   in the north.

   Queried about the Dalby citations, Merriam-Webster Editorial
Department told me:  "A word pronounced approximately 'kai' is an
expression of surprise or amusement in Jamaican Creole and in Sea
Islands Creole (Gullah).  If you take into account the pronunciation
and meaning, you'll see that it does not fit 'okay' either
semantically or phonetically.  There is nothing in the history of
'O.K.' or 'okay' that suggests it has an African-American origin."