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.
Eyes dilate for many reasons. They mainly dilate to control the amount of light that enters the eye. Pupils become smaller when the light is bright, and larger in the dark. Eye doctors dilate eyes to check for signs of disease. Eyes can also dilate as a result of an illness, or another condition or emotion. The circular and radial muscle of the iris control eye dilation. The radial muscle responds to dim light and will cause your pupil to become larger. The circular muscle reacts to bright light and causes the pupil to grow smaller.