An Etymological Dictionary of Astronomy and Astrophysics

The amount of energy, fluid, or particles passing in a given direction in a unit of time.

Etymology (EN): O.Fr. flux, from L. fluxus, p.p. of fluere “to flow,” PIE base *bhleug- (cf. L. flumen “river;” Gk. phluein “to boil over, bubble up,” phlein “to abound”).

Etymology (PE): Šâr “outpouring of water, wine, etc.,” šâridan “to flow (as rivers), with a great noise; to pour,” âbšâr “waterfall;” saršâr “overflowing; brim-full;” Ossetic ægzælyn “to pour down;” Pashto zγâstəl/zγâl- “to swim;” Av. γžār- “to flow;” cf. Skt. ksar- “to flow;” Gk. phtheirein “to destroy, perish.”