What does consanguinity mean?
Consanguinity denotes the fact or degree of relationship between people who descend from a common ancestor — in plain terms, being related by blood. It stands in contrast to affinity, which describes kinship created by marriage, and to legal or adoptive relationships that involve no shared ancestry. The word appears most often in specialised contexts: genealogists use it to chart family lines, lawyers invoke degrees of consanguinity when determining inheritance rights or permissible marriage partners, and physicians consider parental consanguinity when assessing the risk of recessive genetic conditions. Its Latin roots — literally 'with' (con-) 'blood' (sanguis) — make its meaning transparent once known, yet it remains unfamiliar to most general readers. Formal and precise rather than warm, consanguinity is nonetheless a valuable term whenever the distinction between blood relations and relations by marriage matters.
nounThe quality or state of being descended from the same ancestor as another person; kinship by blood, as opposed to kinship by marriage or adoption.
- Kinship by descent from a common ancestor; the state of being related by blood, especially in legal, genealogical, or medical contexts.
"The inheritance laws of the period traced entitlement through consanguinity rather than through marriage."
"Because of their close consanguinity, first cousins are subject to particular genetic counselling recommendations in some countries."
"The court determined that the claimant's consanguinity with the deceased entitled her to a share of the estate."
The plural is rare and typically appears only in legal or academic texts discussing multiple distinct instances or degrees of blood relationship.
"The registry recorded several consanguinities among the noble houses of the region."
In medieval canon law, marriages were forbidden between couples related within seven degrees of consanguinity — so many people had to consult family trees before wedding.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of consanguinity
Consanguinity derives from Latin consanguinitas, formed from com- ('together, with') and sanguis ('blood'), meaning 'shared blood'. The term entered English via Old French consanguinité around the late fourteenth to fifteenth century, initially in ecclesiastical and legal discussions of marriage prohibitions. Cognates appear across the Romance languages (French consanguinité, Spanish consanguinidad, Italian consanguinità), all descending from the same Latin source. The adjective consanguineous developed from the same root and is now the more frequently encountered form in medical writing.
Related word forms
How consanguinity is actually used
Consanguinity is a formal word used chiefly in law, genealogy, medicine (particularly genetics and inherited-disorder risk), and anthropology. In everyday conversation people simply say 'they're related by blood' rather than using this term. It carries no emotional connotation itself — it is a neutral technical descriptor of biological relationship, distinct from affinity (kinship by marriage).
Easily confused with consanguinity
Affinity is kinship created by marriage (relationship by marriage ties), whereas consanguinity is kinship by descent from a common ancestor — a blood relationship.
Sanguine means optimistic or cheerfully confident (or, historically, ruddy-complexioned), while consanguinity refers to shared blood ancestry; they share a Latin root but nothing else.