lias

• POS: Noun
• HYPHEN: Li=as

CIDE DICTIONARY

lias, n. [Cf. F. lias, fr. liais sort of limestone, OF. also liois; perh. of Celtic origin, cf. Armor. liach, leach, a stone, Gael. leac, W. llech. Cf. Cromlech.].

 The lowest of the three divisions of the Jurassic period; a name given in England and Europe to a series of marine limestones underlying the Oölite. See the Chart of Geology.  [1913 Webster]

OXFORD DICTIONARY

lias, n.
1 (Lias) Geol. the lower strata of the Jurassic system of rocks, consisting of shales and limestones rich in fossils.
2 a blue limestone rock found in SW England.

Derivative

liassic adj. (in sense 1).

Etymology

ME f. OF liois hard limestone, prob. f. Gmc