What's the adjective for lineality? Here's the word you're looking for.
lineal
(family) Of a family relationship that includes mothers, fathers, daughters, sons, grandparents, grandchildren, etc., but not siblings; as opposed to collateral.
Inheriting by direct descent; having the right by direct descent to succeed (to).
Composed of lines; delineated.
In the direction of a line; of a line; of or relating to a line; measured on, or ascertained by, a line; linear.
