#bond_servant  someone bound to labor without wages
  supertype:  slave  a person who is owned by someone
  subtype:  bondman.bond_servant__bondsman  a male bound to serve without wages
  subtype:  bondswoman__bondwoman__bondmaid  a female bound to serve without wages
  subtype:  thrall  someone held in bondage
     subtype:  serf__helot__villein  (medieval Europe) a person who is bound to the land and owned by the feudal lord
        subtype:  cottier__cotter  a medieval English villein

No statement uses or specializes bond_servant; click here to add one.