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
Related formsper·i·sto·mal, per·i·sto·mat·ic [per-uh-stuh-mat-ik] /ˌpɛr ə stəˈmæt ɪk/, per·i·sto·mi·al, adjective
From the New Latin
dating back to 1790–1800.
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for peristome
Historical Examples of peristome
Peristome strongly constricted, one-third as broad as the shell, with nine large ovate lamellar, slightly convergent feet.
Peristome small, constricted, scarcely one-fourth as broad as the shell, with twelve to fifteen short triangular vertical feet.
Peristome constricted, with six divergent cylindrical, irregularly curved feet, twice to three times as long as the shell.
The peristome bears a double marginal ring of divergent conical spines, the upper being directed upwards, the lower downwards.
Peristome with a coronet of fifteen to twenty parallel and vertical triangular lamellar feet, nearly as long as the thorax.
British Dictionary definitions for peristome
Derived Formsperistomal or peristomial, adjective
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
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
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
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