exogamyPronunciation: /ɪkˈsɒgəmi, ɛk-/Definition of exogamy noun [mass noun] 1 Anthropology the custom of marrying outside a community, clan, or tribe. Compare with endogamy. 2 Biology the fusion of reproductive cells from distantly related or unrelated individuals; cross-pollination. Derivatives exogamous adjective exogamy in other Oxford dictionaries Definition of exogamy in the US English dictionary