Source : Webster's Revised Unabridged Dictionary (1913)

Triassic \Tri*as"sic\, a. (Geol.)
   Of the age of, or pertaining to, the Trias. -- n. The
   Triassic formation.

Source : WordNet®

Triassic
     n : from 230 million to 190 million years ago; dinosaurs, marine
         reptiles; volcanic activity [syn: {Triassic period}]