(n.) A modification of the bassoon, much deeper in tone.

alpenhorn alphorn alto horn ballad horn baritone bass horn brass choir brass wind brass-wind instrument brasses bugle bugle horn clarion cornet cornet-a-pistons corno di caccia cornopean double-bell euphonium euphonium helicon horn hunting horn key trumpet lituus lur mellophone ophicleide orchestral horn pocket trumpet post horn sackbut saxhorn saxtuba serpent slide trombone sliphorn sousaphone tenor tuba tromba trombone trumpet tuba valve trombone valve trumpet