Code of Federal Regulations Title 31. Money and Finance–Treasury § 31.515.339 Close relative

(a) For purposes of this part, the term close relative used with respect to any person means any individual related to that person by blood, marriage, or adoption who is no more than three generations removed from that person or from a common ancestor with that person.

(b) Example. Your mother's first cousin is your close relative for purposes of this part, because you are both no more than three generations removed from your great-grandparents, who are the ancestors you have in common. Similarly, your husband's great-grandson is your close relative for purposes of this part, because he is no more than three generations removed from your husband. Your daughter's father-in-law is not your close relative for purposes of this part, because you have no common ancestor.