Tampion

Tampion (pronounced tam-pee-uhn)

(1) In ordnance, a wooden plug, or a metal or canvas cover for the muzzle of a gun, a cannon or other piece of ordnance when not in use; a stopper; a bung.

(2) In music, a plug for the upper end of an organ pipe.

(3) An obsolete form of tampon (a plug of absorbent material inserted into a body cavity or wound to absorb fluid).

1425-1475: From the Late Middle English tampyon, a variant of the fourteenth century Middle French tampon & tampion (piece of folded cloth used to stop a hole), a nasalized variant of Old French tapon (tape plug), a diminutive or augmented form of the Old French tape (plug, bung, tap), from the Frankish tappo (stopper, plug), from the Proto-Germanic tappô (plug, tap).  It was cognate with the Old High German zapfo (stopper) and the Old English tæppa (stopper).  The alternative forms were tampeon and tompion.  The use to describe a "canvas or wooden plug futted to the muzzle of a gun to prevent the intrusion of rain or seawater" entered military use in the 1620s.  Tampion is a noun and tampioned an adjective; the noun plural is tampions.

The verb tamp (to fill a hole containing an explosive with dirt or clay before blasting) dates from 1819 and appears to have begun as workmen's slang, possibly as a back-formation from tampion, that word being mistaken as a present participle (tamping).  The noun tamper emerged circa 1865 in the sense of "one who or that which tamps" and was the agent noun from the verb.  In the world of explosive blasting, tamp is still used in the sense of "to plug up a hole with clay, earth, dry sand, sod, or other material, as a prelude to detonation" and in civil engineering generally means (1) to drive in or pack down by frequent gentle strokes & (2) as "tamp the soil" so to render a smooth surface.

Royal Marines fitting tampions to the fourteen inch guns of the battleship HMS Howe.  When fitted, a gun was said to be "tampioned", the word also once common in military medicine when a plug of absorbent material had been inserted into a body cavity or wound to absorb fluid.