Lineal consanguinity is the blood relationship among persons where one is a direct descendant or ascendant of the other. It is the relation in a direct line, such as between a father, son, and grandson.
Lineal consanguinity can either be downward in a direct descending line – as in son, grandson, and great grandson or be upward in a direct ascending line – as in son, father, and grandfather.
See also: Consanguinity; Collateral consanguinity
[Last updated in July of 2021 by the Wex Definitions Team]