Definition of ROOT

2. When the roots of a tree planted in one man s land extend into that
of another, this circumstance does not give the latter any right to the tree,
though such is the doctrine of the civil law; Dig. 41, 1, 7, 13; but such
person has a right to cut off the roots up to his line. Rolle s R. 394, vide
Tree.

3. In a figurative sense, the term root is used to signify the person
from whom one or more others are descended. Vide Descent; Per stirpes.

Source: Bouviers Law Dictionary 1856 Edition