Pronunciation: (an'yu-lus),[key] —n., —pl.-liPronunciation: (-lī"),[key]-lus•es. 1. a ring; a ringlike part, band, or space.
2. Geom.the space between two concentric circles on a plane.
3. the veil remnant on a mushroom stalk. See illus. under mushroom. 4. a growth ring, as on the cross section of a tree trunk, that can be used to estimate age.