glacial period

noun

1. Also called glacial period, ice age. the geologically recent Pleistocene Epoch, during which much of the Northern Hemisphere was covered by great ice sheets.
2. any one of the Permian, Carboniferous, Cambrian, or Precambrian glaciations.

noun

1. any period of time during which a large part of the earth’s surface was covered with ice, due to the advance of glaciers, as in the late Carboniferous period, and during most of the Pleistocene; glaciation
2. (often capitals) the Pleistocene epoch