Why do we call a coin-operated machine that plays music a jukebox?
(Answer below:)

"Juke" derives from Gullah dialect, spoken by people of African descent
living in the Southeastern United States.  Juke joints were originally
"disorderly" houses, places of ill repute, a characterization that had
nothing to do with the quality of their housekeeping.  Eventually the
term also applied to roadhouses that just served liquor.

In the roadhouses juke organs, coin-operated hurdy-gurdies, played
music when you deposited a nickel.  When similar machines playing
records for a nickel were introduced during the swing era, they were
called jukeboxes for their resemblance to the juke organs.  But try to
operate them today with a nickel and the juke will be on you.

(Source: A Dictionary of Americanisms, edited by Mitford M. Mathews)

Will Herzog

 [ See also "Honky-Tonk" and "Barrelhouse" in MMD 970131, in which
 [ Dan Wilson passed on a very reasonable explanation that reaches
 [ even farther into the past.  But I'm curious about the coin
 [ operated "juke organs".  I've not heard this term.  What's this
 [ about?  Orchestrions?  -- Robbie