1. plural of radius; straight lines from the center of a circle to its edge
Usage: geometry
2. plural of radius; the bones on the thumb side of the forearm
Usage: anatomy

Examples

• The circle has three radii drawn from its center to different points on the circumference.
• All radii of a circle are equal in length.
• The mathematician calculated the radii of several concentric circles.
• The X-ray showed fractures in both radii of the patient’s forearms.
• The radii and ulnae are the two bones in each forearm.
• During the accident, she broke one of her radii near the wrist.