n.
Pronunciation: mag- ' n ē -t ə - ˌ sfir, - ' ne-
Function: noun
Date: 1959
: a region of space surrounding a celestial object (as a planet or star) that is dominated by the object's magnetic field so that charged particles are trapped in it
– mag · ne · to · spher · ic \ - ˌ n ē -t ə - ' sfir-ik, - ' sfer- \ adjective