The trombone (Ger. Posaune, Sp. trombón) is a musical instrument in the brass family. Like all brass instruments, sound is produced when the player’s vibrating lips (embouchure) cause the air column inside the instrument to vibrate. The trombone is usually characterised by a telescopic slide with which the player varies the length of the tube to change pitches, although the valve trombone uses three valves like those on a trumpet.
The word trombone derives from Italian tromba (trumpet) and -one (a suffix meaning "large"), so the name means "large trumpet". The trombone has a predominantly cylindrical bore like its valved counterpart the baritone horn and in contrast to its conical valved counterparts, the euphonium and the orchestral horn. The most frequently encountered trombones are the tenor trombone and bass trombone, while the E♭ alto trombone has become less common as tenor technique has extended the upper range of that instrument. The most common variant, the tenor, is pitched in B♭, an octave below the B♭ trumpet and an octave above the B♭ tuba. Trombone music, along with music for euphonium and tuba, is typically written in concert pitch, although exceptions do occur, notably in some brass band music where tenor trombone is presented as a B♭ transposing instrument.
A person who plays the trombone is called a trombonist or trombone player.