An Etymological Dictionary of Astronomy and Astrophysics

The region between a planet’s magnetopause and the bow shock caused by the solar wind.

Etymology (EN): From → magneto- + sheath, from O.E. sceað, scæð, from P.Gmc. *skaithiz (cf. M.Du. schede, Du. schede, O.H.G. skaida, Ger. Scheide “scabbard”).

Etymology (PE): From meqnât-, → magnet, + niyâm “sheath,” from Proto-Iranian *nigāma-, from ni- “down; into,” → ni-, + gāma- “to go, to come” (Av. gam- “to come; to go,” jamaiti “goes;” O.Pers. gam- “to come; to go;” Mod./Mid.Pers. gâm
“step, pace,” âmadan “to come;” cf. Skt. gamati “goes;” Gk. bainein “to go, walk, step;” L. venire “to come;” Tocharian A käm- “to come;” O.H.G. queman “to come;” E. come; PIE root *gwem- “to go, come”); cf. Skt. nigamá- “insertion, incorporation.”