I. (ˈ)trī|asik adjective
Usage: usually capitalized
Etymology: International Scientific Vocabulary triass- (from Latin trias three, triad) + -ic; from the European Triassic being subdivided into the triad of Bunter, Muschelkalk, and Keuper
: of or relating to a division of the Mesozoic in which gymnosperms (as the cycads) are the most distinctive plants, the amphibians decline but the reptiles and ammonites develop rapidly, mammals prob. exist but are few, small, and primitive — see geologic time table
II. noun
( -s )
Usage: usually capitalized
: the Triassic period or system of rocks