JITTER, noun. A nervous action; a tic.

JITTER, noun. (chiefly in the plural) (often with "the") A state of nervousness.

JITTER, noun. (telecommunications) An abrupt and unwanted variation of one or more signal characteristics.

JITTER, verb. (intransitive) To be nervous.

JITTER, noun. (computing) A program or routine that performs jitting.

JITTER, noun. Small rapid variations in a waveform resulting from fluctuations in the voltage supply or mechanical vibrations or other sources.

JITTER, noun. A small irregular movement.