hock (n.1) Look up hock at Dictionary.com
"joint in the hind leg of a horse," mid-15c., earlier hockshin (late 14c.), from Old English hohsinu "sinew of the heel, Achilles' tendon," literally "heel sinew," from hoh "heel," from Proto-Germanic *hanhaz (cognates: German Hachse "hock," Old English hæla "heel"), from PIE *kenk- (3) "heel, bend of the knee."
hock (n.2) Look up hock at Dictionary.com
"Rhenish wine," 1620s, shortening of Hockamore, from German Hochheimer, "(wine) of Hochheim," town on the Main where wine was made; sense extended to German white wines in general.
hock (n.3) Look up hock at Dictionary.com
"pawn, debt," 1859, American English, in hock, which meant both "in debt" and "in prison," from Dutch hok "jail, pen, doghouse, hutch, hovel." The verb is 1878, from the noun.
When one gambler is caught by another, smarter than himself, and is beat, then he is in hock. Men are only caught, or put in hock, on the race-tracks, or on the steamboats down South. ... Among thieves a man is in hock when he is in prison. [G.W. Matsell, "Vocabulum," 1859]