| the offspring of a zebra and a donkey. |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| glacier (glā'shər) Pronunciation Key
A large mass of ice moving very slowly through a valley or spreading outward from a center. Glaciers form over many years from packed snow in areas where snow accumulates faster than it melts. A glacier is always moving, but when its forward edge melts faster than the ice behind it advances, the glacier as a whole shrinks backward. |
A large mass of ice formed over many years that does not melt during the summer. Glaciers move slowly over an area of land such as a mountain valley.
Note: Glaciers exist in high mountains throughout the temperate zones and cover most of Antarctica. Glaciers recede during warm periods and can expand during cold periods, creating ice ages.
Note: A significant percentage of the water of the Earth is locked up in glaciers.