- a ring; a ringlike part, band, or space.
- Geometry. the space between two concentric circles on a plane.
- the veil remnant on a mushroom stalk.
- a growth ring, as on the cross section of a tree trunk, that can be used to estimate age.
Origin of annulus
Examples from the Web for annulus
Historical Examples of annulus
Armillate: with a ring or annulus of raised or different tissue.
Ring: a circle or annulus, usually margining a discolored spot.
The annulus is not persistent, and the gills are crowded and notched.Studies of American Fungi. Mushrooms, Edible, Poisonous, etc.
George Francis Atkinson
Some have referred the name to the Latin or Italian, annulus, or annello.Ancient Armour and Weapons in Europe
This was called the astronomical ring, annulus astronomicus.Finger-Ring Lore
- the area between two concentric circles
- a ring-shaped part, figure, or space
Word Origin for annulus
1560s, medical, from misspelling of Latin anulus "little ring, finger ring," a diminutive of anus (see anus).
- A circular or ring-shaped structure.
- A ringlike figure, part, structure, or marking, such as a growth ring on the scale of a fish.
- A ring or group of specialized cells around the sporangia of many ferns. By changing shape in response to variations in humidity, it breaks open the sporangium and then releases the spores with a whipping motion.
- The ringlike remains of a membrane (called a veil), found around the stipes of certain basidiomycete mushrooms. The presence or absence of an annulus is often used to identify the species of an individual mushroom.
- The figure bounded by and containing the area between two concentric circles.