Learn how to say Triassic correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word Triassic:
relating to or denoting the earliest period of the Mesozoic era, between the Permian and Jurassic periods. See also Permo–Triassic.
(as noun the Triassic or the Trias) the Triassic period or the system of rocks deposited during it.
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