canister (n.)

late 15c., "basket," from Latin canistrum "wicker basket" for bread, fruit, flowers, etc., from Greek kanystron "basket made from reed," from kanna (see cane (n.)). It came to mean "small metal receptacle" (1711) through influence of unrelated can (n.). As short for canister shot, it is attested from 1801, so called for its casing.