lager: [19] Lager is etymologically beer that has been matured by being kept in a ‘store’. English borrowed the term from German lagerbier, a compound based on the noun lager ‘storeroom’ (to which English laager and lair are closely related). => laager, lair[lager etymology, lager origin, 英语词源]
1858, American English, short for lager beer (1845), from German Lagerbier "beer brewed for keeping" some months before being drunk, from Lager "storehouse" (see lair) + Bier "beer."