- (often initial capital letters) the glacial epoch, especially the Pleistocene Epoch.
- another name for glacial period
- Any of several cold periods during which glaciers covered much of the Earth.
- Ice Age. The most recent glacial period, which occurred during the Pleistocene Epoch and ended about 10,000 years ago. During the Pleistocene Ice Age, great sheets of ice up to two miles thick covered most of Greenland, Canada, and the northern United States as well as northern Europe and Russia.