Meaning of magnetotail

mag•ne•to•tail

Pronunciation: (mag-nē'tu-tāl"), [key]
— n. Astron.
  1. the narrow and elongated region of the magnetosphere of the earth or of another planet that extends in the direction away from the sun.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.