The Collaborative International Dictionary of English v.0.48:

Cousin \Cous"in\ (k[u^]z"'n), n. [F. cousin, LL. cosinus,
   cusinus, contr. from L. consobrinus the child of a mother's
   sister, cousin; con- + sobrinus a cousin by the mother's
   side, a form derived fr. soror (for sosor) sister. See
   Sister, and cf. Cozen, Coz.]
   1. One collaterally related more remotely than a brother or
      sister; especially, the son or daughter of an uncle or
      aunt.
      [1913 Webster]

   Note: The children of brothers and sisters are usually
         denominated first cousins, or cousins-german. In
         the second generation, they are called second
         cousins. See Cater-cousin, and Quater-cousin.
         [1913 Webster]

               Thou art, great lord, my father's sister's son,
               A cousin-german to great Priam's seed. --Shak.
         [1913 Webster]

   2. A title formerly given by a king to a nobleman,
      particularly to those of the council. In English writs,
      etc., issued by the crown, it signifies any earl.
      [1913 Webster]

            My noble lords and cousins, all, good morrow.
                                                  --Shak.
      [1913 Webster]