Cornet-à-piston
Cornet-à-piston (k?r"n?t-?-p?s"t?n; F. k?r`n?`?p?s`t?n") , noun
[French]
(Music) A brass wind instrument, like the trumpet, furnished with valves moved by small pistons or sliding rods; a cornopean; a cornet.
Also: Cornet-a-piston