noun. 1  a. An old French dance resembling the gavotte, usually in 3/4 or 2/2 time beginning with an upbeat. 2  A movement in ballet in which the dancer transfers body weight quickly from foot to foot, usually on the balls of the feet, in a series of small steps.
Nystagmus is a condition where the eyes make repetitive movements. The eyes can jerk exclusively in one direction, or make back and forth movements. With nystagmus, the eye can look jittery and can affect both eyes or just one eye.
By Burt Dubow, OD. Nystagmus most commonly causes the eyes to look involuntarily from side to side in a rapid, swinging motion rather than staying fixed on an object or person. Some nystagmuses, however, cause the eyes to jerk sideways or up and down.