| 释义 | polar cap
 polar capn. Either of the regions around a planet's poles that are permanently covered with ice or other frozen material. Also called  polar ice cap.polar cap1.  The mass of permanent ice that covers either of the Earth's polar regions.2.  The mass of frozen carbon dioxide and water that covers either of Mars's polar regions.
 polar cap
 polar cap[′pō·lər ‚kap]  (astronomy) Any of the bright areas covering the poles of Mars, believed to be composed of frozen carbon dioxide and water-ice.   (hydrology) An ice sheet centered at one of the poles of the earth. |