A cousin is a relative with whom one shares a common ancestor. The relations of first cousins are of two people who share a grandparent. It also refers to the son or daughter of an uncle or aunt.
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Children of first cousins are called second cousins. The term removed can be used when referring to the children or parents of cousins. Your first cousins' children are your first cousins once removed, their children will be your first cousins twice removed.
Cousin marriage is marriage between people with a common grandparent or between people who share another relatively recent ancestor. In various cultures and legal jurisdictions, such marriages range...