Genealogy
the systematical investigation and exhibition of the origin, descent, and relations of families (or their "pedigree"). Persons descended from a common father constitute a family. Under the idea of "degree" of relationship is denoted the nearness or remoteness of relationship in which one person stands with respect to another.
A series of several persons, descended from a common progenitor, is called a "line." A line is either "direct" or "collateral." The collateral lines comprehend the several lines which unite in a common progenitor. For illustrating descent and relationship genealogical tables are constructed, the order of which depends on the end in view. The common form of genealogical tables places the common stock at the head, and shows the degree of each descendant by lines. Some tables, however, have been constructed in the form of a tree, in which the progenitor (German , Stammvater, "trunk-father") is placed beneath as if for a root.