Definition of: peristome

(per′ə·stōm) noun
1. Bot. The fringe of delicate teeth, generally some multiple of four, around the mouth of the capsule of mosses.
2. Zool. The parts that surround the mouth; specifically, the lip or margin of the mouth of a univalve; the space between the mouth and the tentacles of a sea anemone.
3. Entomol. The oval margin of the face or border of the mouth in a dipterous insect. Also pe·ris·to·ma (pə·ris′tə·mə), per′i·sto′·mi·um. [<NL peristoma <Gk. peri- around + stoma a mouth]