radius

noun ra·di·us \ ˈrā-dē-əs \

|Updated on: 10 Aug 2018

Examples: radius in a Sentence

Definition of radius

plural radii play \ˈrā-dē-ˌī\ also radiuses

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

See radius defined for English-language learners

See radius defined for kids

Examples of radius in a Sentence

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

Recent Examples of radius from the Web

The study states that within a one-mile radius of the Cavaliers’ Quicken Loans Arena, the restaurant total spiked from roughly 165 to above 210 when James came back.

— ben tobin, USA TODAY, "LeBron James could hurt Cleveland restaurants, ticket sales with departure," 29 June 2018
Census data shows 16 percent of the population within a mile radius of the center is Latino.

— kate magill, Columbia Flier, "Once again, an Oakland Mills Village Center grocery closes," 25 June 2018
Apart from the European Central Bank, occupying two avant-garde towers in Frankfurt’s Ostend (East End), most financial institutions are within a roughly one-mile radius in the city’s western parts and close to the main train station.

— nina adam, WSJ, "Frankfurt: A Business Traveler’s Guide," 22 June 2018
More than 190,000 residents within a three-mile radius enjoy the finest metropolitan lifestyle in elegant high rise residences featuring renowned architecture.

— Houston Chronicle, "By the Numbers: Houston’s Most Lively District," 19 June 2018
More than 800 homes stand within a three-mile radius of the plant, dozens of them sporting anti-CAFO yard signs.

— rick montgomery, kansascity, "Missouri approves permit to expand cattle feedlot by Powell Gardens; appeal expected," 15 June 2018
Within a half-mile radius of the blast, there would be few survivors.

— Daily Intelligencer, "This Is What a Nuclear Bomb Looks Like," 12 June 2018
The area is currently dominated by the aerospace industry— 19 such companies are in a 7-mile radius.

— hannah lang, charlotteobserver, "After investing $100 million in NC, company finally gets OK to make new drug in the US," 3 July 2018
Uranus is about 14 times the mass of Earth and around four times larger in radius.

— john wenz, Popular Mechanics, "We Might Finally Know What Smacked Uranus Sideways," 2 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radius.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of radius

Latin, ray, radius

NEW! Time Traveler

First Known Use: 1578

in the meaning defined at sense 1

See Words from the same year

Other Mathematics and Statistics Terms

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

RADIUS Defined for English Language Learners

radius

noun

Definition of radius for English Language Learners

: a straight line from the center of a circle or sphere to any point on the outer edge; also : the length of this line
: an area that goes outward in all directions from a particular place
medical : the bone in the lower part of your arm on the same side as your thumb

RADIUS Defined for Kids

radius

noun ra·di·us \ ˈrā-dē-əs \

Definition of radius for Students

plural radii \-dē-ˌī\

1 : a straight line extending from the center of a circle to the outside edge or from the center of a sphere to the surface

2 : an area that extends in all directions from a place

Most students live within a radius of five miles from the school.

3 : the bone on the thumb side of the arm between the wrist and the elbow

Medical Dictionary

radius

noun ra·di·us \ ˈrād-ē-əs \

medical Definition of radius

plural radii play \-ē-ˌī\ also radiuses

: the bone on the thumb side of the human forearm or on the corresponding part of the forelimb of vertebrates above fishes that in humans is movably articulated with the ulna at both ends so as to permit partial rotation about that bone, that bears on its inner aspect somewhat distal to the head a prominence for the insertion of the biceps tendon, and that has the lower end broadened for articulation with the proximal bones of the carpus so that rotation of the radius involves also that of the hand