adj. & n.
adj. 1 of the nature of chalk. 2 (Cretaceous) Geol. of or relating to the last period of the Mesozoic era, with evidence of the first flowering plants, the extinction of dinosaurs, and extensive deposits of chalk. °Cf. Appendix II.
n. Geol. this era or system.
[ L cretaceus f. creta chalk ]