means A large earthenware or stoneware beer mug, often fitted with a hinged lid, traditionally associated with German drinking culture.

from Short for German Steinkrug, literally 'stone jug' — Stein meaning 'stone' (a cousin of English 'stone' through their shared Germanic root) plus Krug, 'jug.' English borrowed the clipped form 'stein' in the late 19th century. The famous lid is real history, not legend, though usually credited to sanitation laws meant to keep flies and debris out of drinks during plague-conscious centuries — the anti-plague detail is the popular tale rather than firmly documented fact.