Lias

/ ˈlaɪəs; laɪˈæsɪk /

noun

1. the lowest series of rocks of the Jurassic system

Derived Forms

• Liassic, adjective

Word History and Origins

Origin of Lias¹

C15 (referring to a kind of limestone), C19 (geological sense) from Old French liois, perhaps from lie lees, dregs, so called from its appearance