polar cap

polar cap

n.

1.

a. Either of the regions around the poles of the earth that are permanently covered with ice.

b. A high-altitude icecap.

2. Astronomy Either of the regions around the poles of Mars that are covered with frozen carbon dioxide and water.

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polar cap

1. The mass of ice that covers either of the Earth's polar regions year-round.

2. The mass of frozen carbon dioxide and water that covers either of Mars's polar regions.