[plahy-stuh-seen] 
Geology| 1. | noting or pertaining to the epoch forming the earlier half of the Quaternary Period, beginning about two million years ago and ending 10,000 years ago, characterized by widespread glacial ice and the advent of modern humans. |
| 2. | the Pleistocene Epoch or Series. |
| Pleis·to·cene (plī'stə-sēn') adj. 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. n. The Pleistocene Epoch or its system of deposits. [Greek pleistos, most; see pelə-1 in Indo-European roots + -cene.] |
| Pleistocene (plī'stə-sēn') Pronunciation Key
The earlier of the two epochs of the Quaternary Period, from about 2 million to 10,000 years ago. The Pleistocene Epoch was characterized by the formation of widespread glaciers in the Northern Hemisphere and by the appearance of humans. Mammals included both small forms, such as saber-toothed tigers and horses and giant ones, such as mammoths and mastodons. Almost all the giant mammals, including woolly mammoths, giant wolves, giant ground sloths, and massive wombats disappeared at the end of the Pleistocene and the start of the Holocene. See Chart at geologic time. |
stəˌsin