radius

ra·di·us

noun \ˈrā-dē-əs\

plural ra·dii\-dē-ˌī\ also ra·di·us·es

Definition of RADIUS

1

: a line segment extending from the center of a circle or sphere to the circumference or bounding surface

2

a : the bone on the thumb side of the human forearm; also : a corresponding part of vertebrates above fishes b : the third and usually largest vein of an insect's wing

3

a : the length of a radius <a truck with a short turning radius> b : the circular area defined by a stated radius c : a bounded or circumscribed area

4

: a radial part

5

: the distance from a center line or point to an axis of rotation

Examples of RADIUS

1. Measure the radius of the circle.
2. a radius of 10 inches
3. The new museum is expected to draw people from a wide radius.
4. There are three restaurants within a one-block radius of our apartment.

Origin of RADIUS

Latin, ray, radius

First Known Use: circa 1611

Other Mathematics and Statistics Terms

abscissa, denominator, divisor, equilateral, exponent, hypotenuse, logarithm, oblique, radii, rhomb