The movable metal tube of a trombone which lengthens or shortens the tubing of the instrument, thus changing the fundamental and harmonic series of the instrument, enabling it to hit each chromatic note of its range. A rapid run of notes, without differentiating or accenting each of the intermediate notes. See glissando. An ornamentation of two accessory notes, when performed upwards it is called an "elevation", when downwards, a "double backfall" or a "slur". The small movable metal tube(s) of a brass instrument which lengthens or shortens the tubing of the instrument, thus changing the pitch to bring the instrument, in tune with other instruments in an ensemble. Typically, there is a slide associated with each valve, so they can be tuned individually. Pulling a slide out (or making the tubing longer) will lower the pitch or make the pitch flatter. Pushing a slide in (or making the tubing shorter) will raise the pitch or make the pitch sharper.<br><br>A plastic or glass tube placed over the third or fourth finger of the left hand and used to play "slide" or glissando effects in rock and blues and other forms of traditional music<br><br>A control that has a knob which moves in a straight line and which outputs part of an input voltage according to the position of the knob.