A lineal descendant, in legal usage, refers to a blood relative in the direct line of descent

Kinship

Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. And descent groups, lineages, etc. are treated in their own subsections....

. The children, grandchildren, great-grandchildren, etc. of a person.

Adopted children, for whom adoption statutes create the same rights of heirship as children of the body

Child

Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

, come within the meaning of the term "lineal descendants," as used in a statute providing for the non-lapse of a devise where the devisee predeceases the testator but leaves lineal descendants.

Among Native American tribes in the United States, tribal enrollment can be determined by lineal descent, as opposed to a minimum blood quantum. Lineal descent means that anyone directly descended from original tribal enrollees could be eligible for tribal enrollment, regardless of how much Indian blood they have.