radius

noun ra·di·us \ ˈrā-dē-əs \

|Updated on: 15 Jun 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 average annual household income within a one-mile radius of the development is $109,240, according to a demographic analysis commissioned by the company in late 2017.

— maria l. la ganga, idahostatesman, "More movie theaters. Cushy reclining seats. Eagle Road will go further upscale.," 30 May 2018
Hotel guests get complimentary Tesla transportation within a 5-mile radius.

— alison darosa, sandiegouniontribune.com, "June travel deals: Arizona dude ranch, Eurostar sale," 30 May 2018
More than 800 homes stand within a three-mile radius of the plant.

— rick montgomery, kansascity, "Here's the beef: Missouri cattle feedlot wants to grow; Powell Gardens fears the stink | The Kansas City Star," 27 May 2018
During the initial impact, shock waves flattened trees in massive waves within a radius of nearly 1,000 miles.

— ashley strickland, CNN, "These were the unlikely survivors after dinosaurs went extinct," 24 May 2018
Blue Link will help locate your car – within a one-mile radius, and drop a pin on a map on your smartphone.

— emma jayne williams, star-telegram, "Hyundai’s 2018 Kona small crossover starts at $19,500, offers all-wheel drive | Fort Worth Star-Telegram," 19 May 2018
Tinder already uses location to match people within a certain mile radius, but going off that small screenshot in Morris’ tweet, this location-tracking feature could be more precise.

— ashley carman, The Verge, "Tinder is testing location-tracking features ahead of Facebook’s dating app launch," 11 May 2018
Prochaska said in a two block radius there were neighbors who also had health issues, such as cancer, diabetes and heart conditions.

— karen pilarski, Milwaukee Journal Sentinel, "We Energies promises to take specific steps to protect frustrated neighbors from dust at its coal power plant," 5 Apr. 2018
Some 20,000 people reside within a mile radius of S. H. Bell's facility, including more than 6,000 children.

— maya dukmasova, Chicago Reader, "News / Environment Dangerous levels of heavy metals found at homes near industrial storage facility," 4 May 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