radius - Dictionary Definition : Vocabulary.com

If you're a detective working a crime investigation, you might be told to "search over a one-mile radius," meaning, scope out everything that's within one mile of the crime scene.

The radius of a circle is the distance from its center to the circumference, and if you are working on your geometry homework, or designing anything circular, you'll be writing down a little "r" quite frequently, to stand for "radius." It's also the name of one of the bones in your forearm.

PRIMARY MEANINGS OF: radius

1	n	a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)
2	n	the outer and slightly shorter of the two bones of the human forearm

FULL DEFINITIONS OF: radius

1

n a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)

Type of:: straight line
a line traced by a point traveling in a constant direction; a line of zero curvature

n support consisting of a radial member of a wheel joining the hub to the rim

Synonyms:: spoke, wheel spoke

Type of:: support
any device that bears the weight of another thing

n the length of a line segment between the center and circumference of a circle or sphere

Synonyms:: r

Types:: semidiameter
the apparent radius of a celestial body when viewed as a disc from the earth; radius of curvature
the radius of the circle of curvature; the absolute value of the reciprocal of the curvature of a curve at a given point

Type of:: length
the linear extent in space from one end to the other; the longest dimension of something that is fixed in place

n a circular region whose area is indicated by the length of its radius

“they located it within a radius of 2 miles”

Type of:: part, region
the extended spatial location of something

2

n the outer and slightly shorter of the two bones of the human forearm

Type of:: arm bone
a bone in the arm