n. 1 the science of the earth, including the composition, structure, and origin of its rocks. 2 this science applied to any other planet or celestial body. 3 the geological features of a district. geologic adj. geological adj. geologically adv. geologist n. geologize v.tr. & intr. (also -ise).
[ mod.L geologia (as GEO-, -LOGY) ]