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]

The Collaborative International Dictionary of English v.0.48:

Cousin \Cous"in\, n.
   Allied; akin. [Obs.] --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cousin
    n 1: the child of your aunt or uncle [syn: cousin, first
         cousin, cousin-german, full cousin]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "cousin":
   aunt, auntie, blood brother, brethren, brother, bub, bubba, bud,
   buddy, country cousin, cousin once removed, cousin twice removed,
   daughter, father, first cousin, foster brother, frater,
   grandnephew, grandniece, granduncle, great-aunt, great-uncle,
   half brother, kid brother, mother, nephew, niece, nuncle, nunks,
   nunky, second cousin, sis, sissy, sister, sister-german, sistern,
   son, stepbrother, stepsister, unc, uncle, uncs, uterine brother



Bouvier's Law Dictionary, Revised 6th Ed (1856):

COUSIN, domest. rel. Cousins are kindred who are the issue of two brothers
or two sisters, or of a brother and a sister. Those who descend from the
brother or sister of the father of the person spoken of are called paternal
cousins; maternal cousins are those who are descended from the brothers or
sisters of the mother. Vide 2 Bro. C. C. 125; 1 Sim. & Stu. 301; 3 Russ. C.
C. 140; 9 Sim. R. 386, 457.