[ge.ol.o.gy] n, pl -gies [NL geologia, fr. ge- + -logia -logy] (1735) 1 a: a science that deals with the history of the earth and its life esp. as recorded in rocks b: a study of the solid matter of a celestial body (as the moon)
2: geologic features
3: a treatise on geology -- ge.ol.o.gist n