A slide is a part of a wind instrument consisting of two (or more) pieces of tubing fitted one closely inside the other, and used to vary the overall length of the tube, and therefore the pitch of the instrument.
Often two sets of tubes are used, with a U bend attaching them; this arrangement is called a single slide.
A double slide, where two U-shaped slides are braced together and move on four inner tubes, is found on the B♭ contrabass trombone.
Slides are used in three main ways:
This article relating to brass instruments is a stub.