ethnos, nation: ethnic, ethnology.
eu, well; as a prefix: eucharist, euphony, euphemism, ev-angel.
Gamos, marriage: mono-gamous.
gaster (gastr-), stomach: gastric.
gen-, beget—genos, race; genesis, origin: genea-logy, genesis, genetic.
gē, the earth: ge-o-graphy, ge-o-logy, ge-o-metric.
glōssa (glōtta), tongue: glossary, glottis, epiglottis, poly-glot.
gnō-sis, knowledge: gnome, gnostic.
gōnia, angle: diagonal, pentagon.
grapho, write; gramma, writing: graphic, epi-graphy, grammar.