Webster’s Revised Unabridged Dictionary · 1913
Jurassic
Ju·ras′sic, a. (Geol.) Of the age of the middle Mesozoic, including, as divided in England and Europe, the Lias, Oölite, and Wealden; — named from certain rocks of the Jura mountains. — n. The Jurassic period or formation; — called also the Jura.