Garbology – study of garbage Gastroenterology – study of stomach; intestines Gastronomy – study of fine dining Gemmology – study of gems and jewels Genealogy – study of descent of families Genesiology – study of reproduction and heredity Genethlialogy – art of casting horoscopes Geochemistry – study of chemistry of the earth's crust Geochronology – study of measuring geological time Geogeny – science of the formation of the earth's crust Geogony – study of formation of the earth Geography – study of surface of the earth and its inhabitants Geology – study of earth's crust Geomorphogeny – study of the origins of land forms Geoponics – study of agriculture Geotechnics – study of increasing habitability of the earth Geratology – study of decadence and decay Gerocomy – study of old age Gerontology – study of the elderly; aging Gigantology – study of giants Glaciology – study of ice ages and glaciation Glossology – study of language; study of the tongue Glyptography – art of engraving on gems Glyptology – study of gem engravings Gnomonics – the art of measuring time using sundials Gnosiology – study of knowledge; philosophy of knowledge Gnotobiology – study of life in germ-free conditions Graminology – study of grasses Grammatology – study of systems of writing Graphemics – study of systems of representing speech in writing Graphology – study of handwriting Gromatics – science of surveying Gynaecology – study of women’s physiology Gyrostatics – study of rotating bodies