Where does the term “Bock Beer” come from and What does Bock Beer mean?

One couldn’t do better than quote from the 1856 Illinois State Register:

“There is which is called ‘bock’, in English buck or an item in an issue of a Bavarian lager beer goat, and is so called because of its great strength making its consumers prance and tumble about like these animals.”

This beer, incidentally, requires about two months for brewing, being brewed usually in midwinter, and is usually drunk in early spring.