What does exogamous mean?
Exogamous is an adjective describing marriage or mating practices in which partners are drawn from outside a defined social unit — a clan, village, lineage, or community — rather than within it. The term belongs mainly to the vocabulary of anthropology, where exogamous rules are among the most widespread marriage customs known across human societies: many cultures have required members to look outward for spouses, often to build alliances between groups and avoid unions among close kin. The word also appears in biology, where exogamous reproduction denotes the joining of gametes from genetically unrelated individuals. Its opposite is endogamous, describing marriage confined within the group. Formal and technical in register, exogamous derives ultimately from the Greek elements exo ('outside') and gamos ('marriage'). For anyone reading about kinship systems or population genetics, it is an indispensable term for describing how groups regulate who may marry whom.
adjectiveRelating to or characterized by exogamy: the custom of seeking a marriage partner only outside one's own social group, clan, or community.
- (Anthropology) Relating to or practising exogamy — the requirement to take a spouse from outside one's own kinship group, clan, or community.
- (Biology) Relating to the union of gametes from individuals that are genetically unrelated or dissimilar.
"The tribe maintained exogamous marriage rules, requiring young people to find spouses beyond their own clan."
"In many Australian Aboriginal societies, exogamous marriage rules bound people to seek partners from specific distant clans."
"The population's exogamous breeding patterns introduced fresh genetic variation into an otherwise isolated lineage."
Swap one letter and you reverse the whole rule of marriage: exogamous societies insist you marry out, while endogamous ones insist you stay in.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of exogamous
Exogamous comes from the Greek elements exō ('outside') and gamos ('marriage'), the same root that gives us monogamy, polygamy, and bigamy. The underlying concept was coined as the noun exogamy by the Scottish anthropologist John Ferguson McLennan in the 19th century, during early debates about the origins of marriage customs, and the adjective followed soon after in scholarly use. It shares its Greek root gamos with biological vocabulary such as gamete, reflecting the word's dual life in both anthropology and the life sciences.
Related word forms
How exogamous is actually used
A formal, scholarly term used chiefly in anthropology, sociology, and biology; it rarely appears in casual conversation. In anthropology it typically refers to culturally mandated rules rather than individual preference, so calling a couple 'exogamous' usually implies a group-level norm rather than a personal choice.
Easily confused with exogamous
Endogamous describes marrying within one's own social group, whereas exogamous describes marrying outside it — they are direct opposites.