n. The act of flowing; fluxation; change.n. That which flows; that which changes; a flux.n. Specifically— In medicine: An abnormal flow or determination of blood or other humor to any organ, as the brain; active hyperemia. A catarrh.n. The running or reduction of metals to a fluid state; fusion.n. Something, as an indication, which constantly varies.n. In mathematics, the rate of change of a continuously varying quantity; the differential coefficient relatively to the time.