An orbit is a type of scratch used by turntablists. It is generally any scratch that incorporates both a forward and backward movement, or vice versa, of the record in sequence.
The orbit was developed by DJ Disk who incorporated the flare after being shown by DJ Q-Bert.
Usually when someone is referring to an orbit, they are most likely talking about flare orbits. For example, A 1 click forward flare and a 1 click backward flare in quick succession (altogether creating 4 very quick distinct sounds) would be a 1 click orbit. A 2 click forward flare and a 2 click backward flare in quick succession (altogether creating 6 very distinct sounds) would be a 2 click orbit, etc. Orbits can be performed once as a single orbit move, or sequenced to produce a cyclical never ending type of orbit sound.