From Middle High German boc, poc, from Old High German boc, from Proto-West Germanic *bukk. Cognate to English buck, Bavarian Bock, Dutch bok, Norwegian bukk, Swedish bock, Danish buk.

From a southern German alteration of Einbeck, a brewery town in Lower Saxony, where the beer originally hails from. The Low German placename suffix -beck (“-brook”) was reinterpreted in southern dialects as the plural of Bock (etymology 1 above). Compare a fuller form still in Bavarian Oambock, Ambock.

Borrowed from Romani bokh (“hunger”); ultimately from Sanskrit बुभुक्षा (bubhukṣā). Reinforced and perhaps semantically influenced by Bock (etymology 1) in its sexual sense. First attested in the second half of the 20th century and originally belonging to the Rotwelsch cant. Distant doublet of Funktion.