Definition
In law, a cousin is a collateral blood relative descended from the brother or sister of one's father or mother — that is, a first cousin in modern common usage. Legal instruments frequently require precision about degree: a paternal cousin descends from the brother or sister of one's father; a maternal cousin descends from the brothers or sisters of one's mother. Cousins-german are first cousins — those sharing one set of grandparents.
Beyond the primary meaning, cousin has carried a secondary formal usage in English royal and governmental instruments, where the crown addressed earls and certain high nobles as "cousin," a usage reflecting political ceremony rather than biological relationship.
Common Language
Modern common usage (Wiktionary): Primarily the child of one's uncle or aunt; more loosely, any collateral relative (especially a more distant one) who is not a direct ancestor or descendant. Ordinal qualifiers such as "first cousin" and "second cousin" and the modifier "once removed" are used to specify degree.
Historical common usage (Webster's 1913): "The son or daughter of an uncle or aunt." Also a title formerly given by a king to a nobleman, particularly members of the council; in English writs, signifying any earl.
The gap between common and legal meaning is narrow for the core definition, but significant in two directions. First, older legal sources use cousin more broadly than modern speakers expect — Burrill notes it was applied in early books to a brother, sister, or uncle — which means a researcher reading medieval or early modern instruments cannot assume cousin carries its modern restricted sense. Second, the honorific usage (cousin as a royal address to an earl) appears in English crown instruments without any familial content whatsoever, and can mislead a researcher into assuming a blood relationship where none exists.
Common Confusion
Cousin-german vs. cousin: Cousins-german are first cousins. The term german (from the Latin germanus, meaning of the same stock) distinguishes full first cousins from more distant collateral relatives who might also be loosely called cousins in older instruments. A researcher finding cousin in an eighteenth- or nineteenth-century will or deed should not automatically read it as a first cousin relationship; older usage was broader.
Cousin by marriage vs. cousin by blood: Anderson's notes that cousin was sometimes used to mean a cousin by marriage. This matters acutely in inheritance and intestacy contexts, where consanguinity — blood relationship — is legally operative and relationship by marriage generally is not.
Recognized Forms
/SUBTYPES
Paternal cousin: A cousin descended from the brother or sister of one's father.
Maternal cousin: A cousin descended from the brother or sister of one's mother.
Cousin-german (first cousin): The child of one's aunt or uncle; collateral kin in the fourth degree.
Cousin by marriage: A collateral relative connected through marriage rather than blood; legally distinct from a blood cousin in most inheritance contexts.
Cousin (honorific): In English crown instruments, the formal address to an earl, carrying no blood-relationship meaning.
Why It Matters in Research
The primary research trap with cousin is temporal and jurisdictional imprecision in the sources themselves. Burrill explicitly documents that in the old books the term was applied to a brother, sister, or uncle — categories modern researchers would never subsume under cousin. Any search of early common law materials, Year Books, or pre-modern chancery records using cousin as a kinship marker requires caution about this broader historical application.
In wills, deeds, and intestacy proceedings, the degree of relationship matters for legal entitlement. A bequest to "my cousin" in a nineteenth-century will does not resolve itself simply: courts have had to determine whether the testator meant first cousins only, all collateral relatives, or even relatives by marriage. Anderson's observation that cousin was sometimes extended to cousins by marriage adds a further complication when tracing property devolution.
For researchers working with English crown instruments — royal commissions, letters patent, formal writs — the honorific usage is a significant false flag. Finding that a monarch addressed someone as cousin establishes noble rank, not family connection.
The paternal/maternal distinction matters in jurisdictions or historical periods with different rules for inheritance through the paternal versus maternal line — a consideration in both English common law development and civil law systems influencing American colonial law.
Historical Dictionary Support
The core definition is consistent across all six sources: the child of one's uncle or aunt, collateral kin in the fourth degree. Black's (both editions) and Bouvier agree precisely on the paternal/maternal distinction and on cousins-german as first cousins.
Burrill adds the most historically significant dimension: the broad early usage encompassing brother, sister, and uncle, grounded in Littleton and Coke. This older meaning is entirely absent from Black's and Bouvier, which reflect the term's narrowed modern legal sense. Researchers relying solely on Black's would have no indication that cousin once carried this wider meaning in English legal sources.
Anderson contributes the marriage-extension usage, which the other dictionaries do not address and which is practically important for inheritance research.
Rapalje & Lawrence's entry is fragmentary and offers little substantive guidance; the cross-reference to COSINAGE is more useful than the entry itself, pointing researchers toward the related action for recovery of land by collateral heirs.
Webster's 1913 confirms both the primary meaning and the honorific usage, aligning well with the legal sources on both points.
Jurisdictional Note
American intestacy statutes typically specify degrees of kinship with precision, and cousin as a standalone term in statutory text usually means first cousin. English law historically used cousin more fluidly, and researchers working with pre-twentieth-century English materials should be alert to the broader applications documented in Burrill. Civil law jurisdictions (and states with civil law heritage, notably Louisiana) calculate degrees of relationship differently, which affects where cousins fall in succession priority.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Consanguinity and Degrees of Kinship; Intestate Succession; Descent and Distribution