Family relationships
First-degree family links are those between parents and children.
Second-degree links include brothers and sisters, and grandchildren and grandparents.
At the third degree, there are great-grandparents, uncles and aunts, and nieces and nephews.
At the fourth degree, we find a person’s first cousins.
MORE in the diagram.
In short, the degree of kinship represents the number of intermediaries between two people, going back to the common ancestor, then returning to them.