An Etymological Dictionary of Astronomy and Astrophysics

Meteo.: A whirling mass of water or air.

A pattern of rotation in which the rotation direction rotates by 360° along any path which surrounds the centre of the vortex.

Etymology (EN): From L. vortex, variant of vertex “whirlpool; whirlwind, an eddy of water, wind, or flame;” from stem of vertere “to turn,” cognate with Pers. gardidan, as below.

Etymology (PE): Gerdšâr (on the model of gerdâb “whirlpool” and gerdbâd “whirlwind”), from gard present stem of gardidan “to turn, to change” (Mid.Pers. vartitan “to change, to turn;” Av. varət- “to turn, revolve;” cf. Skt. vrt- “to turn, roll,” vartate “it turns round, rolls;” L. vertere “to turn;”
O.H.G. werden “to become;” PIE base *wer- “to turn, bend”) + šâr, from šâré, → fluid.