peristome
noun
peri·stome
ˈper-ə-ˌstōm 
1
: the fringe of teeth surrounding the orifice of a moss capsule
2
: the region around the mouth in various invertebrates
Examples of peristome in a Sentence
Recent Examples on the Web
With the peristome teeth extended, the capsule is only about 1 millimeter wide, yet from afar the mosses often give a drab blackish impression.
—
Cecilia Rodriguez, Forbes, 5 Feb. 2023
With the peristome teeth extended, the capsule is only about one millimeter wide, yet from afar the mosses often give a drab blackish impression.
—Alan Taylor, The Atlantic, 9 Jan. 2023
Only when wet, the peristome surface is slippery for insects, so that most ant visitors become trapped.
—Ncbi Rofl, Discover Magazine, 20 Feb. 2013
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Cecilia Rodriguez, Forbes, 5 Feb. 2023
With the peristome teeth extended, the capsule is only about one millimeter wide, yet from afar the mosses often give a drab blackish impression.
—Alan Taylor, The Atlantic, 9 Jan. 2023
Only when wet, the peristome surface is slippery for insects, so that most ant visitors become trapped.
—Ncbi Rofl, Discover Magazine, 20 Feb. 2013
Cite this Entry
“Peristome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/peristome. Accessed 31 Oct. 2025.
Copy CitationMedical Definition
peristome
noun
peri·stome
ˈper-ə-ˌstōm
: the area surrounding the mouth or cytostome of a protozoan
Love words? Need even more definitions?
Merriam-Webster unabridged
Share