Source : Webster's Revised Unabridged Dictionary (1913)

Pessary \Pes"sa*ry\, n.; pl. {Pessaries}. [L. pessarium, pessum,
   pessus, Gr. ?: cf. F. pessaire.] (Med.)
   (a) An instrument or device to be introduced into and worn in
       the vagina, to support the uterus, or remedy a
       malposition.
   (b) A medicinal substance in the form of a bolus or mass,
       designed for introduction into the vagina; a vaginal
       suppository.

Source : WordNet®

pessary
     n : a contraceptive device consisting of a flexible dome-shaped
         cup made of rubber or plastic; it is filled with
         spermicide and fitted over the uterine cervix [syn: {diaphragm},
          {contraceptive diaphragm}]