son-in-law

from WordNet (r) 3.0 (2006)

son-in-law
    n 1: the husband of your daughter

from The Collaborative International Dictionary of English v.0.48

Son-in-law \Son"-in-law`\, n.; pl. {Sons-in-law}.
   The husband of one's daughter; a man in his relationship to
   his wife's parents.
   [1913 Webster]

         To take me as for thy son in lawe.       --Chaucer.
   [1913 Webster]

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

SON-IN-LAW, in Latin called gener. The husband of one's daughter.