The trombone is one of the most recognizable instruments in the brass family. It is pitched lower than the trumpet, and higher than the tuba. It is a simple, yet unique instrument in that it uses a slide to change from note to note, rather than valves. The trombone has been in existence for centuries under various forms and names, but has remained relatively unchanged for many years. It dates back to the mid 1400's, where it emerged from England & Belgium and was called a Sackbut. The exact etymology and meaning of the term “sackbut” is not certain, but is thought to be a derivation of the Old French term, sacquer, “to draw out.” The Trombone, as it is called today, is simply the Italian Tromba (trumpet) with the suffix one, meaning 'big trumpet'.

The modern trombone is not very different from its medieval ancestors. It still has the distinct s-shape, but is in general larger in bore than it's predecessors. Its characteristics are a cylindrical bore, meaning that the diameter of the tubing stays relatively the same throughout the length of the horn, a handslide, and a bell section that extends out proportionately about 1/3 of the length of the slide when assembled. The bell section is different than that of the early trombone. The flare is now more sudden and closer to the end of the bell section, rather than being funnel-like.

There are several different types of trombones in use in today's ensembles. The three types of trombones most often used are the alto trombone, tenor trombone, and bass trombone. Of these three, the most common is the tenor trombone.

Mutes
A variety of mutes can be used with the trombone to alter its timbre. Many are held in place with the use of cork grips, including the straight, cup, harmon and pixie mutes. Some fit over the bell, like the bucket mute. In addition to this, mutes can be held in front of the bell and moved to cover more or less area for a wah-wah effect - such as the "hat" and plunger.

Mouthpieces
The mouthpiece is actually a separate part of the trombone and can be interchanged with similarly-sized trombones from different manufacturers. Mouthpiece dimensions vary in length, diameter, rim shape, and cup depth. Each variation affects timbre (tone quality), and is a highly personal decision of advanced trombone players. Typically, a symphonic trombonist will choose a mouthpiece with a deeper cup length and sharper inner rim shape in order to produce a rich, full-textured tone quality that is desired in most symphony orchestras. A jazz trombonist, on the other hand, may choose a shallower cup in order to achieve a thinner, less Teutonic tone quality. However, these decisions vary from player to player.