An Etymological Dictionary of Astronomy and Astrophysics

The sharp outer boundary of the plasmasphere, at which the plasma density decreases by a factor of 100 or more.

Etymology (EN): → plasma + pause “break, cessation, stop,” from M.Fr. pause, from L. pausa “a halt, stop, cessation,” from Gk. pausis “stopping, ceasing,” from pauein “to stop, to cause to cease.”

Etymology (PE): → plasma + marz “frontier, border, boundary,” from Mid.Pers. marz “boundary;” Av. marəza- “border, district,” marəz- “to rub, wipe;” Mod.Pers. parmâs “contact, touching” (→ contact), mâl-, mâlidan “to rub;” PIE base *merg- “boundary, border;” cf. L. margo “edge” (Fr. marge “margin”); P.Gmc. *marko;
Ger. Mark; E. mark, margin.