Definition of twitches:
(n) :
A brief, small (sometimes involuntary) movement out of place and then back again; a spasm.
(n) :
(physiology) A brief, contractile response of a skeletal muscle elicited by a single maximal volley of impulses in the neurons supplying it.
(v) :
(intransitive) To perform a twitch; spasm.
(v) :
(transitive) To cause to twitch; spasm.
(v) :
(transitive) To jerk sharply and briefly.
(n) :
(informal) Action of spotting or seeking out a bird, especially a rare one.