Triassic
Pronunciation: /trʌɪˈasɪk/
Definition of Triassic
adjective
Geology- relating to or denoting the earliest period of the Mesozoic era, between the Permian and Jurassic periods. See also Permo–Triassic.
The Triassic lasted from about 245 to 208 million years ago. Many new organisms appeared following the mass extinctions of the end of the Palaeozoic era, including the earliest dinosaurs and ammonites and the first primitive mammals