Pleistocene
Pronunciation: /ˈplʌɪstəsiːn/
adjective
Geology- relating to or denoting the first epoch of the Quaternary period, between the Pliocene and Holocene epochs.
- (as noun the Pleistocene) the Pleistocene epoch or the system of deposits laid down during it.
- The Pleistocene epoch lasted from 1,640,000 to about 10,000 years ago. It was marked by great fluctuations in temperature that caused the ice ages, with glacial periods followed by warmer interglacial periods. Several forms of fossil human, leading up to modern humans, appeared during this epoch

Origin:
mid 19th century: from Greek pleistos 'most' + kainos 'new'