|glacier (ˈɡlæsɪə, ˈɡleɪs-)|
|a slowly moving mass of ice originating from an accumulation of snow. It can either spread out from a central mass (continental glacier) or descend from a high valley (alpine glacier)|
|[C18: from French (Savoy dialect), from Old French glace ice, from Late Latin glacia, from Latin glaciēs ice]|
|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.