bun: [14] The word bun first crops up in 1371, in an Anglo-Latin document relating to different types of bread. Its origins, however, are completely shrouded in mystery. Equally obscure, but presumably unrelated, is another word bun, which in the 16th century meant ‘squirrel’. By the 19th century we find it being used for ‘rabbit’, and it survives in its familiar form bunny. [bun etymology, bun origin, 英语词源]