ice·cap or ice cap (īs'kāp') n. An extensive dome-shaped or platelike perennial cover of ice and snow that spreads out from a center and covers a large area, especially of land.
A dome-shaped body of ice and snow that covers a mountain peak or a large area and spreads out under its own weight. Ice caps have an area of less than 50,000 square km (19,500 square mi). Compare ice sheet.