(literary) a vessel used in ancient times for receiving anonymous reports or secret information; shaped like a bamboo tube, it allowed documents to be inserted but not removed

A type of bedding made by rolling a quilt into a long tube for someone to sleep inside; also written as [[被筒|被筒|bei4 tong3]]

(literary) an ancient container used to collect secret reports or tip-offs, shaped like a bamboo tube so that documents can be inserted but not removed; also written [[缿筩|缿筩|xiang4 tong3]]