The radius around a particular point is the distance from it in any direction.
Nigel has searched for work in a ten-mile radius around his home.
2. countable noun
The radius of a circle is the distance from its centre to its outside edge.
He indicated a semicircle with a radius of about thirty miles. [+ of]
radius in British English
(ˈreɪdɪəs)
nounWord forms: plural-dii (-dɪˌaɪ) or -diuses
1.
a straight line joining the centre of a circle or sphere to any point on the circumference or surface
2.
the length of this line, usually denoted by the symbol r
3.
the distance from the centre of a regular polygon to a vertex (long radius) or the perpendicular distance to a side (short radius)
4. anatomy
the outer and slightly shorter of the two bones of the human forearm, extending from the elbow to the wrist
5.
a corresponding bone in other vertebrates
6.
any of the veins of an insect's wing
7.
a group of ray florets, occurring in such plants as the daisy
8.
a.
any radial or radiating part, such as a spoke
b.
(as modifier)
a radius arm
9.
the lateral displacement of a cam or eccentric wheel
10.
a circular area of a size indicated by the length of its radius
the police stopped every lorry within a radius of four miles
11.
the operational limit of a ship, aircraft, etc
Word origin
C16: from Latin: rod, ray, spoke
radius in American English
(ˈreɪdiəs)
nounWord forms: pluralˈradiˌi (ˈreɪdiˌaɪ) or ˈradiuses
1.
a raylike or radial part, as a spoke of a wheel
2.
a.
any straight line extending from the center to the periphery of a circle or sphere
b.
the length of such a line
3.
a.
the circular area or distance limited by the sweep of such a line
no house within a radius of five miles
b.
the distance a ship or airplane can travel and still return to its point of origin without refueling
4.
an extent, scope, range, etc. of a limited or specified kind
within the radius of one's experience
5.
a.
the shorter and thicker of the two bones of the forearm on the same side as the thumb
b.
a corresponding bone of the forelimb of a four-legged animal
6. Zoology
a.
any of the planes of division of the body of a radially symmetrical animal
b.
any of various longitudinal veins in the wing of an insect
Word origin
L, rod, spoke (of a wheel), hence radius, ray (of light), ? akin to radix, root1
Examples of 'radius' in a sentence
radius
So its radius is 15 miles.
Times, Sunday Times (2016)
They were yesterday combing a mile radius around the scene.
The Sun (2008)
Keep one mile radius from this restaurant if the weather's good.
Times, Sunday Times (2007)
This is clear for the circle, which is defined as the shape with a fixed radius from the centre.
Times, Sunday Times (2009)
Worker bees forage over an area three miles in radius, returning to the exact spot on the landing board from which they took off.
Times, Sunday Times (2013)
Contributors must be within a five-mile radius of a certain point, such as a university building.
Times, Sunday Times (2015)
One circle made the head and another touching circle (with radius three times as big) made the body.
Times, Sunday Times (2012)
The menu changes daily and at least 80 per cent of the ingredients are sourced from just a 20 mile radius.
The Sun (2011)
Somehow it all works beautifully, as does the menu of produce sourced from within a five-mile radius of the restaurant.
Times, Sunday Times (2014)
There is enough to see within a few miles' radius, with seaside resorts and many places of historic interest inland.
Conil, Jean & Conil, Christopher (ed) A Passion for Food (1989)
There is accommodation for more than 600 on campus and the remainder live in villages mostly within a five-mile radius of the college.
Times, Sunday Times (2008)
Word lists with
radius
bone
In other languages
radius
British English: radius NOUN
from point The radius around a particular point is the distance from it in any direction.
He has searched for work in a ten-mile radius around his home.
American English: radius
Brazilian Portuguese: raio
Chinese: 范围
European Spanish: radio
French: rayon
German: Umkreis
Italian: raggio
Japanese: 半径
Korean: 반경
European Portuguese: raio
Latin American Spanish: radio
British English: radius NOUN
circle The radius of a circle is the distance from its center to its outside edge.
He indicated a semicircle with a radius of about thirty miles.
American English: radius
Brazilian Portuguese: raio
Chinese: 半径
European Spanish: radio
French: rayon
German: Radius
Italian: raggio
Japanese: 半径
Korean: 반지름
European Portuguese: raio
Latin American Spanish: radio
All related terms of 'radius'
long radius
the distance from the centre of a regular polygon to a vertex
radius vector
a line joining a point in space to the origin of polar or spherical coordinates
short radius
the perpendicular distance from the centre of a regular polygon to a side
cruising radius
the greatest distance that an aircraft or ship can cruise , away from and back to a certain point without refueling
turning radius
the smallest circle in which a vehicle can turn
radius of action
the maximum distance that a ship, aircraft, or land vehicle can travel from its base and return without refuelling
radius of gyration
a length that represents the distance in a rotating system between the point about which it is rotating and the point to or from which a transfer of energy has the maximum effect. Symbol : k or r . In a system with a moment of inertia I and mass m , k 2 = I / m
Schwarzschild radius
the radius of a sphere ( Schwarzschild sphere ) surrounding a non-rotating uncharged black hole , from within which no information can escape because of gravitational forces
radius of curvature
the absolute value of the reciprocal of the curvature of a curve at a given point; the radius of a circle the curvature of which is equal to that of the given curve at that point