Definitions

1. noun

Plural of annulus; a ring or ring-shaped object, especially one made of metal or stone.

“The ancient temple’s entrance was adorned with intricately carved annuli.”

2. noun

In biology, a ring or ring-shaped structure, especially one formed by growth or by the aggregation of cells.

“The annuli of the fungus formed a distinctive pattern on its cap.”

3. noun

In mathematics, a ring-shaped region or a ring-shaped graph.

“The mathematician studied the properties of annuli in topological spaces.”