1. a ring-shaped object or structure
Usage: technical
2. the space between two concentric circles
Usage: geometry
3. a ring-shaped part of a plant or animal
Usage: biology

Examples

• The annulus of the tree trunk showed distinct growth rings.
• In geometry class, we calculated the area of the annulus between the two circles.
• The mushroom’s annulus was clearly visible around the stem.
• The engineer designed an annulus-shaped gasket for the pipe joint.
• The annulus in the cross-section revealed the age of the specimen.
• Saturn’s rings form a series of annuli around the planet.