- third, 3rd, tertiary - coming next after the second and just before the fourth in position
Antonym: cardinal (indirect, via ordinal)
- Tertiary, Tertiary period - from 63 million to 2 million years ago
--1 is a kind of period, geological period
--1 is a part of Cenozoic, Cenozoic era, Age of Mammals
--1 has parts:Pliocene, Pliocene epoch; Miocene, Miocene epoch; Oligocene, Oligocene epoch; Eocene, Eocene epoch; Paleocene, Paleocene epoch