Prepared by Elisabeth Lindsay.
An ancestor is someone from whom you are descended, it can be your parents, grandparents, or someone generations back in your family tree. A direct-line ancestor (also known as a progenitor) represents a direct, parent-to-child relationship from one generation to the next. By contrast, a collateral-line relative represents something other than a direct-line relationship such as the spouse and children of siblings; aunts; uncles; and cousins, etc.
Most genealogists and family history researchers focus on tracing direct-line ancestors; and proving a direct-line relationship is required for membership in most heritage societies. However, collateral-line research is extremely important in providing clues to direct-line ancestors.