calcareous /kælˈkɛəɹi.əs/ adjective2 •Resembling, containing, or composed of calcium carbonate or limestone; chalky.The traveller from the coast, who, after plodding northward for a score of miles over calcareous downs and corn-lands, suddenly reaches the verge of one of these escarpments[.] — 1891 •Growing in a chalky habitat. formsmore calcareous · most calcareous