n.1. a dancing or leaping motion, specifically one seen as a result of chorea. 2. the mode of conduction of nerve impulses along myelinated nerve fibers. See saltatory conduction. 3. the phenomenon in which a sensation is felt at a site other than that where it was evoked. For example, auditory saltation is an illusion in which a train of clicks, the first half of which is presented at one location and the other half of which is presented at a second location, is perceived as originating not only from the anchor points but also from locations between them. 4. a sudden evolutionary variation or modification of a species due to large-scale genetic mutation. 5. an abrupt transition or sudden development in the course of an illness. [from Latin saltatio, “dance”]