Tertiary period ter·tia·ry·period uncommon noun 1. from 63 million to 2 million years ago SynonymsTertiaryTertiary period Related words Broader terms period Parts Cenozoic Part of PlioceneMioceneOligoceneEocenePaleocene WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
