1. Plural of annulus; ring-shaped objects or geometric figures, especially the area between two concentric circles.
Usage: mathematics; geometry

Examples

• The architect designed the plaza with several annuli of different colored stone.
• In geometry class, we calculated the area of annuli by subtracting the inner circle from the outer circle.
• The tree's growth rings form annuli that reveal its age.
• The solar eclipse created a stunning view of annuli of light around the moon.
• Engineers used annuli in the design of the bearing system.