P0197200 (pĕr′ĭ-stōm′)n.1. Botany A fringe of toothlike appendages surrounding the mouth of a moss capsule.2. Zoology The area or parts around the mouth in certain invertebrates.per′i·sto′mal(-stō′məl), per′i·sto′mi·al(-stō′mē-əl) adj. EncyclopediaSeeperistome