Daily AncestorThird cousin
A third cousin is a relative who shares great-great-grandparents with you, but no closer ancestors: the child of a parent's second cousin.
Third cousins descend from the same great-great-grandparents through different children of that couple. Their parents were second cousins, and their grandparents were first cousins.
Using the counting rule: great-great-grandparent has two greats, and two plus one makes third cousins. When a letter or family Bible calls someone a third cousin, treat it as a claim to test: trace both lines back to the shared couple before relying on it.
As seen in a recordFamily letter, 1870s
Mrs. Orpha Dunwiddy, who is a third cousin to my mother
How to cite this page
Daily Ancestor. "Third cousin." Dictionary of Old Record Words. https://dailyancestor.com/dictionary/relationships/third-cousin. Last checked 2026-10-12.