radius
noun
ra·di·us
| \ ˈrā-dē-əs
\
\
plural radii\ ˈrā-dē-ˌī
\
also radiuses
\
also radiuses
Definition of radius
1
: a line segment extending from the center of a circle or sphere to the circumference or bounding surface
2a
: 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
3a
: 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 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.
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Recent Examples on the Web
The Sedgwick County Commission made the decision to protect aviation interests after planner Dave Yearout told commissioners that large windmills can affect airport and flight operations within a 5-mile radius, The Wichita Eagle reported. — USA TODAY, "Rocket’s last blast, Alaska drought, million-dollar ham: News from around our 50 states," 23 Aug. 2019 How to visit Located south of the intersection of I-70 and I-75, Dayton lies within a 600-mile radius of two-thirds of the country’s population, making it the perfect weekend destination. — National Geographic, "Visit America’s newest adventure capital," 22 Aug. 2019 Radio-telemetry on sage grouse has determined that leks ideally have no or few trees within a 6-mile (9.5-kilometer) radius, which gives nesting sage grouse hens the best chance to raise their chicks. — Washington Post, "Massive juniper tree-cutting project aims to aid sage grouse," 21 Aug. 2019 Since arriving in Bushwick this year, the company has acquired 20 buildings within a half-square-mile radius, for a total of about 200 bedrooms, and Mr. Bokobza said there are another 30 buildings in the pipeline. — Stefanos Chen, New York Times, "A Gentler Way to Gentrify?," 16 Aug. 2019 But trees had been scorched over a five-mile radius, with all their branches blown off. — Jennifer Ouellette, Ars Technica, "New research on Tunguska finds such events happen less often than we thought," 17 July 2019 In addition to these features, John Deere owners love the cruise control, tight turn radius, and separate gas pedals for forward and reverse. — Paige Szmodis, Popular Mechanics, "The 10 Best Riding Mowers to Shape up Your Lawn This Season," 29 May 2019 Aha, the equivalent of DoorDash or Postmates in the U.S. Its drones can carry food and small consumer goods in a 2.5-mile radius, soon to expand to 5 miles with the introduction of more powerful drones from China’s DJI. — Christopher Mims, WSJ, "Your Drone-Delivered Coffee Is (Almost) Here," 30 Mar. 2019 Ad buyers can target ads to specific locations — say, a mile radius around a particular landmark — and typically have to pay more to reach this narrower audience. — Ryan Nakashima, The Seattle Times, "Google tracks your movements, like it or not," 13 Aug. 2018These 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.
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More Definitions for radius
radius
noun
English Language Learners Definition of radius
technical
: 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
See the full definition for radius in the English Language Learners Dictionary
radius
noun
ra·di·us
| \ ˈrā-dē-əs
\
\
plural radii\ -dē-ˌī \
Kids Definition of radius
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
radius
noun
ra·di·us
| \ ˈrād-ē-əs
\
\
plural radii\ -ē-ˌī
\
also radiuses
\
also radiuses
Medical Definition of radius
: 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
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