early 15c., "plug, bung," from Middle French tampon (15c.), nasalized variant of Old French tapon "piece of cloth to stop a hole" (14c.), a suffixed form of Frankish *tappo "stopper, plug," related to Old High German zapfo and Old English tæppa "stopper" (see tap (n.1)). Meaning "wooden plug for the muzzle of a gun" (to keep out rain or seawater) is recorded from 1620s.
