noun

1. Obsolete a collateral relative more distant than a brother or sister, descended from a common ancestor
2. the son or daughter of one's uncle or aunt: also called first cousin, full cousin, or cousin-german: one's second cousin is a child of one's parent's first cousin; one's first cousin once removed is a child of one's first cousin (or, conversely, a first cousin of one's parent)
3. loosely any relative by blood or marriage
4. a person or thing thought of as somehow related to another our Mexican cousins
5. a title of address used by one sovereign to another sovereign or to a nobleman

Etymology: ME cosin < OFr < L consobrinus, orig., child of a mother's sister, also cousin, relation < com-, with + sobrinus, cousin on the mother's side < base of soror, sister