can (n.)youdaoicibaDictYouDict[can 词源字典]
Old English canne "a cup, container," from Proto-Germanic *kanna (cognates: Old Saxon, Old Norse, Swedish kanna, Middle Dutch kanne, Dutch kan, Old High German channa, German Kanne). Probably an early borrowing from Late Latin canna "container, vessel," from Latin canna "reed," also "reed pipe, small boat;" but the sense evolution is difficult.

Modern "air-tight vessel of tinned iron" is from 1867 (can-opener is from 1877). Slang meaning "toilet" is c. 1900, said to be a shortening of piss-can. Meaning "buttocks" is from c. 1910.[can etymology, can origin, 英语词源]