[ per-uh-stohm ]
/ ˈpɛr əˌstoʊm /


Botany. the one or two circles of small, pointed, toothlike appendages around the orifice of a capsule or urn of mosses, appearing when the lid is removed.
Zoology. any of various structures or sets of parts that surround or form the walls of a mouth or mouthlike opening.

Origin of peristome

From the New Latin word peristoma, dating back to 1790–1800. See peri-, -stome


per·i·sto·mal, per·i·sto·mat·ic [per-uh-stuh-mat-ik] /ˌpɛr ə stəˈmæt ɪk/, per·i·sto·mi·al, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for peristome

British Dictionary definitions for peristome

/ (ˈpɛrɪˌstəʊm) /


a fringe of pointed teeth surrounding the opening of a moss capsule
any of various parts surrounding the mouth of invertebrates, such as echinoderms and earthworms, and of protozoans

Derived forms of peristome

peristomal or peristomial, adjective

Word Origin for peristome

C18: from New Latin peristoma, from peri- + Greek stoma mouth
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for peristome

[ pĕrĭ-stōm′ ]

A fringe of toothlike appendages surrounding the mouth of the spore capsule of some mosses. The teeth unfold under damp conditions and curl up under dry conditions to disperse spores gradually.
The area or parts around the mouth in certain invertebrates, such as the echinoderms.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.