"barrel or cask for soap or liquor; iron vessel," c.1400, from Old French ponchon, ponson "wine vessel" (13c.), of unknown origin. Uncertain connection with puncheon "slab of timber, strut, wooden beam used as a support in building" (mid-14c.). Punch, n.2 in the drink sense is too late to be the source of the "cask" sense.

"pointed tool for punching or piercing" used by masons, also "die for coining or seal-making," mid-14c.; see punch, n.1. Meaning "stamp, die" is from c.1500, a specialized use.