designating or of the first geologic epoch of the Quaternary Period, characterized by a series of advancing and retreating continental glaciers in the Northern Hemisphere and the development of modern humans and toolmaking cultures
See Pleistocene in American Heritage Dictionary 4
(plīˈstə-sēnˌ)
adjective
Of or belonging to the geologic time, rock series, or sedimentary deposits of the earlier of the two epochs of the Quaternary Period, characterized by the alternate appearance and recession of northern glaciation, the appearance and worldwide spread of hominids, and the extinction of numerous land mammals, such as the mammoths, mastodons, and saber-toothed tigers. See Table at geologic time.