There are several synonyms for the term "rapid eye movements." One common term is REM, which stands for rapid eye movement sleep. This phase of sleep is characterized by increased brain activity and rapid eye movements. Another synonym for rapid eye movements is saccades. Saccades are rapid movements of the eyes that occur during normal visual processing and are essential for vision. Nystagmus is another term used to describe rapid eye movements, which can be involuntary and associated with neurological conditions. Finally, some scientists use the term oculomotion to describe rapid eye movements, which includes both saccades and other eye movements during visual processing.