The Collaborative International Dictionary of English v.0.48:

bond-servant \bond-servant\, Bond servant \Bond"
serv`ant\(s[~e]rv`ant).
   A slave; one who is bound to service without wages.
   [1913 Webster]

         If thy brother . . . be waxen poor, and be sold unto
         thee; thou shalt not compel him to serve as a bond
         servant: but as an hired servant.        --Lev. xxv.
                                                  39, 40.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bond servant
    n 1: someone bound to labor without wages