designating or of the third geologic era of the Phanerozoic Eon, usually subdivided into the Tertiary and Quaternary periods and characterized by the development of birds and mammals
ceno- (< Gr kainos: see -cene) + -zoic
See Cenozoic in American Heritage Dictionary 4
Of, belonging to, or designating the latest era of geologic time, which includes the Tertiary Period and the Quaternary Period and is characterized by the formation of modern continents, glaciation, and the diversification of mammals, birds, and plants. See Table at geologic time.
The Cenozoic Era.
Origin: Greek kainos, new; see ken- in Indo-European roots