Source : WordNet®

glacial epoch
     n 1: any period of time during which glaciers covered a large
          part of the earth's surface; "the most recent ice age
          was during the Pleistocene" [syn: {ice age}, {glacial
          period}]
     2: from two million to 11 thousand years ago; extensive
        glaciation of the northern hemisphere; the time of human
        evolution [syn: {Pleistocene}, {Pleistocene epoch}]