stepson

from WordNet (r) 3.0 (2006)
stepson
    n 1: the son your spouse by a former marriage
    
from The Collaborative International Dictionary of English v.0.48
Stepson \Step"son`\, n. [AS. ste['o]psunu.]
   A son of one's husband or wife by a former marriage.
   [1913 Webster]
    
from Bouvier's Law Dictionary, Revised 6th Ed (1856)
STEP-SON. In Latin privignus, is the son of one's wife, or of one's husband. 
    

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