Age of Mammals, Cenozoic, Cenozoic era - approximately the last 63 million years

Holocene, Holocene epoch, Recent epoch - approximately the last 10,000 years

Pleistocene, Pleistocene epoch, Glacial epoch - from two million to 11 thousand years ago; extensive glaciation of the northern hemisphere; the time of human evolution

geological period, period - a unit of geological time during which a system of rocks formed; "ganoid fishes swarmed during the earlier geological periods"