a. | 1. | (Geol.) Of the age of the middle Mesozoic, about 190 to 140 million years ago, including, as divided in England and Europe, the Lias, Oölite, and Wealden; - named from certain rocks of the |
Noun | 1. | Jurassic - from 190 million to 135 million years ago; dinosaurs; conifers Synonyms: Jurassic period |