Source : Webster's Revised Unabridged Dictionary (1913)

Sempstress \Semp"stress\, n.
   A seamstress.

         Two hundred sepstress were employed to make me shirts.
                                                  --Swift.

Source : WordNet®

sempstress
     n : someone who makes or mends dresses [syn: {dressmaker}, {modiste},
          {needlewoman}, {seamstress}]