Saccade: Abrupt rapid small movements of both eyes, such as when the eyes scan a line of print. The saccades can be divided into two distinct groups: the major saccades that are easily observed with the naked eye and the minor saccades that are virtually unobservable without special instrumentation.
The word saccade is borrowed from the French. It is derived from the Old French sachier meaning to shake. In horse riding, a saccade is the bruque shaking given to the reins of a horse as a signal to the horse. Also called saccadic movement.