designating or of the first geologic period of the Mesozoic Era, characterized by the breakup of Pangea, the development of tall forests of cycads and conifers, and the presence of the first dinosaurs, turtles, frogs, and small mammals
See Triassic in American Heritage Dictionary 4
(trī-ăsˈĭk)
adjective
Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the first period of the Mesozoic Era, characterized by the diversification of land life, the rise of dinosaurs, and the appearance of the earliest mammals. See Table at geologic time.