The Collaborative International Dictionary of English v.0.48:

Jupon \Ju*pon"\, Juppon \Jup*pon"\, n. [F. jupon, fr. jupe
   skirt, Sp. aljuba a Moorish garment, Ar. jubba.] [Written
   variously jupe, jump, juppo, etc.]
   [1913 Webster]
   1. A sleeveless jacket worn over the armor in the 14th
      century. It fitted closely, and descended below the hips.
      --Dryden.
      [1913 Webster]

   2. A petticoat. --Halliwell.
      [1913 Webster]