'Age of Mammals' definitions:

Definition of 'Age of Mammals'

(from WordNet)
noun
Approximately the last 63 million years [syn: Cenozoic, Cenozoic era, Age of Mammals]

Definition of 'Age of mammals'

From: GCIDE
  • Mammal \Mam"mal\, n.; pl. Mammals. [L. mammalis belonging to the breast, fr. mamma the breast or pap: cf. F. mammal.] (Zool.) One of the Mammalia. [1913 Webster]
  • Age of mammals. See under Age, n., 8. [1913 Webster]