Definition of peristome in English:



  • 1Zoology
    The parts surrounding the mouth of various invertebrates.

    • ‘The peristome can seem quite large.’
    • ‘Other mature modifications, such as change in the shape of the peristome, are also inconsistently observed in Paleozoic ammonoids.’
    • ‘The autozooids have small apertures and often preserve long peristomes inclined at an acute angle to the colony surface.’
    • ‘Spines and tube feet surrounding the peristome function in locomotion, burrowing, and food-gathering.’
    • ‘Ammonites are complete, many with preserved peristomes.’
  • 2Botany
    A fringe of small projections around the mouth of a capsule in mosses and certain fungi.

    • ‘The sporophytes also develop peristomes and a spongy layer.’


Late 18th century: from modern Latin peristoma, from Greek peri- ‘around’ + stoma ‘mouth’.