the later of two divisions of the Precambrian era, during which the earliest plants and animals are assumed to have lived
Compare Archaeozoic
adjective
2.
of or formed in the late Precambrian era
Proterozoic in American English
(ˌprɑtərəˈzoʊɪk; ˌ proʊtəroʊˈzoʊɪk)
adjective
[sometimesp-]
designating or of the geologic eon characterized by the development of sedimentary rock, shallow seas, and the first soft-bodied, marine invertebrates; Precambrian, esp. late Precambrian
Idioms:
the Proterozoic
Word origin
< Gr proteros, former, compar. of pro, forward (see pro-1) + zo- + -ic