Quaternary
adjective geology specialized uk/kwəˈtɜː.nər.i/ us/ˈkwɑː.t̬ɚ.ner.i/
第四纪的（迄今约250万前至今的地质时间段，这期间现代人出现）
from or referring to the period of time from about 2.5 million years ago to the present, in which modern humans appeared
the Quaternary period 第四纪
Quaternary glaciation 第四纪冰川化
the Quaternary
noun [ S ] us
第四纪
the Quaternary period