COUSIN, n. 1. In a general sense, one collaterally related more remotely than a brother or sister. But, 2. Appropriately, the son or daughter of an uncle or aunt; the children of brothers and sisters being usually denominated cousins or cousin-germans. In the second generation, they are called second cousins. 3. A title given by a king to a nobleman, particularly to those of the council. COUSIN, a. Allied.