pes·sa·ry / ˈpesərē/ • n. (pl. -ries) a small soluble block that is inserted into the vagina to treat infection or as a contraceptive. ∎  an elastic or rigid device that is inserted into the vagina to support the uterus.

pessary †suppository XIV; instrument to remedy uterine displacement XVIII. — late L. pessārium, f. late L. pessum, -us — Gr. pessós, -ón draught-board, oval stone used in a game, medicated plug; see -ARY.

pessary (pess-er-i) n.
1. a plastic device, often ring-shaped, that fits into the vagina and keeps the uterus in position: used to treat prolapse.

2. (vaginal suppository) a plug or cylinder of soft material containing a drug that is fitted into the vagina for the treatment of such disorders as vaginitis.