Flūx'ion, n.
(flŭk/shun), n. [Lat. fluxio, Fr. & Sp. fluxion, It. flussione.]
Sense 1. The act of flowing. Cotgrave.
Sense 2. The matter that flows. Wiseman.
Sense 3. A constantly varying indication.
Less to be counted than the fluxions of sun-dials. De Quincey.
Sense 4. (Math.) The infinitely small increase or decrease of a variable or flowing quantity in a certain infinitely small and constant period of time; the rate of variation of a fluent; an increment; a differential.
Sense 5. (pl.) (Math.) A method of analysis developed by Newton, and based on the conception of all magnitudes as generated by motion, and involving in their changes the notion of velocity or rate of change. It has been superseded by the method of integrals and differentials.