Definition
Collateral kinsmen are relatives who share a common ancestor but do not descend from one another. They occupy the same family tree without standing in a direct line of descent — neither is the ancestor of the other. Brothers and sisters are collateral kinsmen to each other; an uncle and his nephew are collateral kinsmen; cousins of any degree are collateral kinsmen. The term stands in contrast to lineal kinsmen, who descend in a direct line — parent to child to grandchild.
The concept is foundational to the law of intestate succession, where the proximity of a collateral relative to the decedent determines inheritance priority when no lineal descendants or surviving spouse exist to take the estate.
Common Confusion
COLLATERAL KINSMEN vs. LINEAL KINSMEN: Every relative is either lineal or collateral — there is no third category. Lineal kinsmen ascend or descend in a straight line from the decedent (parents, grandparents, children, grandchildren). Collateral kinsmen branch off from a shared ancestor but never stand in that direct line. A researcher who conflates the two categories will misread intestacy statutes and inheritance schedules, since most legal frameworks exhaust lineal heirs before turning to collaterals, and then rank collaterals by degree of relationship.
COLLATERAL KINSMEN vs. COLLATERAL (other legal uses): The word "collateral" carries independent, unrelated meanings throughout the law — collateral security (property pledged as loan security), the collateral source rule in tort law, and collateral matters in evidence. These uses share no conceptual connection to collateral kinship. Context will ordinarily resolve the ambiguity, but researchers moving between primary sources should be alert to the shift.
Why It Matters in Research
Intestacy research is the primary context. In historical probate records, wills, and statutes of distribution, collateral kinsmen appear as the residual class of heirs — those entitled to take when the decedent left no surviving spouse, children, or parents. Understanding which relatives qualify as collateral and in what degree is essential to tracing succession chains in historical estate records.
Degree of relationship matters acutely. Most intestacy frameworks rank collateral kinsmen by how many generational steps separate them from the common ancestor and then from the decedent. Siblings (one step up, one step down) take before first cousins (two steps up, two steps down). Historical statutes often use the civil-law method or the canon-law method of computing degree, and these methods produce different results for the same relatives. A researcher comparing a seventeenth-century English probate record to a nineteenth-century American intestacy schedule must determine which counting method each jurisdiction applied.
Half-blood complications: Historical sources vary on whether half-blood collaterals — relatives sharing only one common ancestor rather than two — inherit equally with whole-blood collaterals or take a reduced share. Some jurisdictions excluded half-blood collaterals entirely in certain degrees. This question generated substantial litigation and statutory variation, and the answers differ markedly across time and place.
The term itself has receded from modern usage. Contemporary statutes typically speak of "brothers and sisters," "aunts and uncles," "cousins," or simply "relatives of the Nth degree" rather than invoking "collateral kinsmen" as a term of art. Researchers reading historical statutes, treatises, or judicial opinions will encounter the phrase frequently; modern statutory compilations will rarely use it.
Historical Dictionary Support
Black's and Bouvier's definitions are substantively identical and jointly establish the core rule: collateral kinsmen descend from one and the same common ancestor but not from one another. Bouvier provides more illustrative examples — siblings, uncle and nephew, cousins — which confirm that the category encompasses the full range of branching relatives, not merely close ones. Rapalje & Lawrence offers no independent definition, deferring by cross-reference, suggesting the term was treated as settled and uncontroversial by the late nineteenth century.
What the historical sources do not address is the computational mechanics — how courts and legislatures actually measured the degree of relationship between collaterals for inheritance purposes. Treatises on real property and domestic relations (including Kent's Commentaries and Blackstone's Commentaries, Book II) fill that gap. The historical dictionaries also do not address the half-blood question, jurisdictional variation in excluding or limiting collateral inheritance, or the point at which collateral kinship becomes so remote that the estate escheats to the state. These are live research questions the dictionary entries leave unanswered.
Jurisdictional Note
Intestacy treatment of collateral kinsmen varies significantly. Some jurisdictions cap inheritance at a specific degree of collateral relationship, beyond which property escheats; others allow collaterals of any degree to inherit. The half-blood question is resolved differently across American states, and historical English law on this point diverged from early American statutory approaches. Researchers working with multi-jurisdictional estates should not assume uniformity.
Encyclopedia Cross-Reference
The Law Mind Criminal Law Encyclopedia: Collateral Consequences of Criminal Conviction (criminal_244) — tangentially relevant only; the "collateral" usage there is unrelated to kinship.