radius

plural radii · plural radiuses

1. anatomyThe long bone in the forearm, on the side of the thumb.

   It is also obvious, and proved by experiment, that the rotatory motions observed in the hand proceed from the rotatory motions of the radius.

   1808, John Barclay, The Muscular Motions of the Human Body, →OCLC, page 396

2. biologyThe lighter bone (or fused portion of bone) in the forelimb of an animal.
3. biologyOne of the major veins of the insect wing, between the subcosta and the media; the vein running along the costal edge of the discal cell.

   Synonyms: R

4. geometryA line segment between any point of a circle or sphere and its center.

   Fatima claims to have visited all the bars within a five-mile radius of her Manhattan apartment.

   2 more examples

   We start with spherical geometries. The two geometries on spheres of radiuses R₁ and R₂ are obviously identical if R₁ = R₂; moreover, the converse also holds.

   1994, Viacheslav V. Nikulin, Igor R. Shafarevich, translated by Miles Reid, Geometries and Groups, Springer, page 194

   The velocity dispersions of early- and late-type galaxies in compact groups change little with groupcentric radius; the radii sampled are less than 100~h#123;-1#125; kpc, smaller than the radii typically sampled by members of massive clusters of galaxies.

   2016, Jubee Sohn, Ho Seong Hwang, Margaret J. Geller, Antonaldo Diaferio, Kenneth J. Rines, Myung Gyoon Lee, Gwang-Ho Lee, “Compact Groups of Galaxies with Complete Spectroscopic Redshifts in the Local Universe”, in JKAS, volume 2015

5. geometryThe length of this line segment.

   This contribution reduces with increasing distance p from the emitting surface element dA, due to conservation of energy, as the wave energy distributed across the spherical wave front remains constant, while the radius increases during ...

   1998, Dieter Schuocker, Handbook of the Eurolaser Academy, Springer Science & Business Media, →ISBN, page 51

6. Anything resembling a radius, such as the spoke of a wheel, the movable arm of a sextant, or one of the radiating lines of a spider's web.

   […] I can do more with a Quadrant, Sextant or Octant, of 1 foot Radius, furniſhed with Teleſcopical Sights and Screws, then ^([sic]) can poſſibly be done with any other Inſtrument, furniſhed only with Common Sights, though 10, 20, 30, nay threeſcore foot Radius; […]

   1674, Robert Hooke, Animadversions on the Firſt Part of the Machina Coelestis of the […] Aſtronomer Johannes Hevelius […] , page 43

7. graph theoryThe minimum eccentricity of any vertex, for a given graph.

present singular third person radiuses · participle present radiusing · participle past radiused · past radiused

1. transitiveTo give a rounded edge to.

   A comfortable grip is ensured by smoothing the surface of the handle and radiusing the edge.

   2014, Anil Mital, Anoop Desai, Anand Subramanian, Product Development, page 358

1. abbreviationinitialismuncountablecomputingInitialism of Remote Authentication Dial-In User Service.