the snug-fitting engine part that is forced back and forth within a cylinder by the pressure of combustion, steam, etc. and a reciprocating connecting rod
Music a sliding valve moved in the cylinder of a brass instrument to change the pitch
Piston,
Walter 1894-1976; U.S. composer
See piston in American Heritage Dictionary 4
(pĭsˈtən)
noun
A solid cylinder or disk that fits snugly into a larger cylinder and moves under fluid pressure, as in a reciprocating engine, or displaces or compresses fluids, as in pumps and compressors.
Music A valve mechanism in brass instruments for altering the pitch.