noun, plural ra·di·i [rey-dee-ahy] /ˈreɪ diˌaɪ/, ra·di·us·es.
Origin of radius
Related Words for radiuspurview, ambit, span, extension, space, interval, reach, orbit, expanse, limit, extent, compass, boundary, spoke, semidiameter
Examples from the Web for radius
Contemporary Examples of radius
Another requirement was that the Colombian National Police would not be permitted within a 12-mile radius of his prison.Pablo Escobar’s Private Prison Is Now Run by Monks for Senior Citizens
June 7, 2014
These were then spread over a 300-mile radius, covered in ravines, gorges and pine forests.The Bosnia Atrocities, the World’s Greatest Forensic Puzzle
December 1, 2013
Khazaee was referring to a 25-mile radius travel ban on Iranian diplomats.Iran’s Foreign Minister Loves Facebook Despite Banning It at Home
October 9, 2013
Part of its plan is to have as many suppliers as possible within a 250-mile radius.A Little Apple Goes a Long Way
December 9, 2012
People there are born, go to school, get married, grow old, and die within a 50-mile radius.Did My Education Cost Too Much?
September 12, 2012
Historical Examples of radius
Delve from the surface of your sphere to its heart, and at once your radius joins every other.
R represents the radius of the curve upon which the vehicle is moving.American Rural Highways
T. R. Agg
If he kept her out of the radius of disapproval, she might never feel a shadow of regret.The Prisoner
It was then that Wilson stepped into the radius of shallow light.The Web of the Golden Spider
Frederick Orin Bartlett
There isn't a well like mine in a radius of a hundred miles.The Forbidden Trail
noun plural -dii (-dɪˌaɪ) or -diuses
- any radial or radiating part, such as a spoke
- (as modifier)a radius arm
Word Origin for radius
1590s, "cross-shaft," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle," of unknown origin. Perhaps related to radix "root," but Tucker suggests connection to Sanskrit vardhate "rises, makes grow," via root *neredh- "rise, out, extend forth;" or else Greek ardis "sharp point."
The geometric sense first recorded 1610s. Plural is radii. Meaning "circular area of defined distance around some place" is attested from 1953. Meaning "shorter bone of the forearm" is from 1610s in English (the Latin word had been used thus by the Romans).