The Collaborative International Dictionary of English v.0.48:
Saccade \Sac*cade"\, n. [F.] (Man.) A sudden, violent check of a horse by drawing or twitching the reins on a sudden and with one pull. [1913 Webster]WordNet (r) 3.0 (2006):
saccade n 1: a rapid, jerky movement of the eyes between positions of rest 2: an abrupt spasmodic movement [syn: jerk, jerking, jolt, saccade]