The fringe of teeth around the orifice of the capsule of mosses. It consists of 4, 8, 16, 32, or 64 teeth, and may be either single or double. [1913 Webster]
The lip, or edge of the aperture, of a spiral shell. [1913 Webster]
Peristome, n.
1 Bot. a fringe of small teeth around the mouth of a capsule in mosses and certain fungi.
2 Zool. the parts surrounding the mouth of various invertebrates.