1. a straight line from the center of a circle to any point on its edge
Usage: geometry
2. the length of such a line; half the diameter of a circle
Usage: geometry
3. a circular area measured outward from a central point

Examples

• The radius of the circle is 5 centimeters.
• Draw a line from the center to the edge to show the radius.
• The explosion could be heard within a radius of ten miles.
• Police searched within a two-mile radius of the crime scene.
• The doctor examined the patient’s broken radius bone.
• All houses within a three-block radius lost power during the storm.