'Cretaceous' definitions:

Definition of 'cretaceous'

(from WordNet)
adjective
Abounding in chalk
adjective
Of or relating to or denoting the third period of the Mesozoic era
noun
From 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants [syn: Cretaceous, Cretaceous period]

Definition of 'Cretaceous'

From: GCIDE
  • Cretaceous \Cre*ta"ceous\ (kr[-e]*t[=a]"sh[u^]s), a. [L. cretaceus, fr. creta chalk. See Crayon.]
  • 1. Having the qualities of chalk; abounding with chalk; chalky; as, cretaceous rocks and formations. See Chalk. [1913 Webster]
  • 2. (Geol.) Of, pertaining to, or designating, the period of time following the Jurassic and preceding the Tertiary, generally given as from 144 million years b. p. to 65 million years b. p.. Also called