An Etymological Dictionary of Astronomy and Astrophysics

Opposite to or reversing something.
Math.: Involving two variables that are in a mathematical relationship where, when one increases, the other decreases and vice versa.

Etymology (EN): From L. inversus, p.p. of invertere, → invert.

Etymology (PE): Vârun “inverse, upside down,” from vâ- “back, backward, again, re-,” variant of bâz-, from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] “away, from;” Av. apa- [pref.] “away, from,”
apaš [adv.] “toward the back;” cf. Skt. ápāñc “situated behind.”