An Etymological Dictionary of Astronomy and Astrophysics

General: Lasting for only a short time; not permanent.
Physics: A non-periodic signal of short duration. A sudden pulse of voltage or current.

Etymology (EN): From L. transiens “passing over or away,” pr.p. of L. transire “to go or cross over,” from → trans- “cross” + ire “to go.”

Etymology (PE): Gozarâ “transient,” from gozar present stem of gozaštan “to pass, cross, transit,” variant gozâštan “to put, to place, let, allow;” Mid.Pers. widardan, widâštan “to pass, to let pass (by);” O.Pers. vitar- “to pass across,” viyatarayam “I put across;” Av. vi-tar- “to pass across,” from vi- “apart, away from” (O.Pers. viy- “apart, away;” Av. vi- “apart, away;” cf. Skt. vi- “apart, asunder, away, out;” L. vitare “to avoid, turn aside”) + O.Pers./Av. tar- “to cross over;” → trans-.