A sudden jerking movement.
The sounding of two violin strings together by using a sudden strong pressure of the bow.
A rapid jerky movement of the eye (voluntary or involuntary) from one focus to another.
The act of checking a horse quickly with a single strong pull of the reins.
To make a rapid jerking movement to focus elsewhere.
The motion of something that twitches.
Compulsive birdwatching by people (twitchers) who travel long distances to see rare species.
That twitches.