An Etymological Dictionary of Astronomy and Astrophysics

The principle of conscious life; the vital principle in humans, animating the body or mediating between body and soul (Dictionary.com).

Etymology (EN): M.E., from L. spiritus “a breathing, breath; breath of life,” related to spirare “to blow, breathe.”

Etymology (PE): Minu “spirit;” Mid.Pers. mênôg “spirit;” Av. mainyu- “mind, mentality, mental force, inspiration,” from mān- “to think,” → mind.