bock : Idioms & Phrases

• noun a very strong lager traditionally brewed in the fall and aged through the winter for consumption in the spring
  bock.
  

WordNet

Bock" beer`

Etymology

G. bockbier; bock a buck + bier beer; -- said to be so named from its tendency to cause the drinker to caper like a goat.

Definitions

1. A strong beer, originally made in Bavaria. Also written buck beer.

Webster 1913