Collateral relative

Collateral kin descend from the same ancestor as you but along a different branch. Webster's 1828 dictionary gives the example of the children of brothers, who have different fathers but a common grandfather. Lineal relatives, in contrast, descend one from another: parent, child, grandchild.

The difference matters in inheritance. With no will, courts put a spouse and lineal descendants first, so collateral kin inherit mainly when there are none. In research, collateral lines are worth tracing because a sibling's or cousin's records may name the ancestor yours leave out.