ice cap

noun2

1. •
   A permanent expanse of ice encompassing a large geographical area, as for example in Earth's polar zones (polar ice) or at high elevation.

   • The ocean beneath the arctic ice cap hosts many unique organisms adapted to the cold and shortage of light.
   • The ice cap of Kilimanjaro is shrinking, and some researchers believe it will disappear within the next one hundred years.
2. •
   (historical) An ice pack designed to be worn on the head.

   • After the use of ice caps for some days it is well to provide cool bathing for the head, at least three times daily. — 1903