# radius

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## ra·di·us

(rā′dē-əs)*n.*

*pl.*

**ra·di·i**(-dē-ī′) or

**ra·di·us·es**

**1.**

*Abbr.*

**r**or

**rad.**

*Mathematics*

**a.**A line segment that joins the center of a circle with any point on its circumference.

**b.**A line segment that joins the center of a sphere with any point on its surface.

**c.**A line segment that joins the center of a regular polygon with any of its vertices.

**d.**The length of any such line segment.

**2.**A circular area measured by a given radius: every family within a radius of 25 miles of the city center.

**3.**A bounded range of effective activity or influence: the operating radius of a helicopter.

**4.**A radial part or structure, such as a mechanically pivoted arm or the spoke of a wheel.

**5.**

*Anatomy*

**a.**A long, prismatic, slightly curved bone in humans, the shorter and thicker of the two forearm bones, located on the lateral side of the ulna.

**b.**A similar bone in many other vertebrates.

[Latin,

*ray, spoke of a wheel, radius*; see**ray**^{1}.]## radius

(ˈreɪdɪəs)*n*,

*pl*

**-dii**(-dɪˌaɪ)

*or*

**-diuses**

**1.**(Mathematics) a straight line joining the centre of a circle or sphere to any point on the circumference or surface

**2.**(Mathematics) the length of this line, usually denoted by the symbol

*r*

**3.**(Mathematics) 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)

*anatomy*the outer and slightly shorter of the two bones of the human forearm, extending from the elbow to the wrist

**5.**(Zoology) a corresponding bone in other vertebrates

**6.**(Zoology) any of the veins of an insect's wing

**7.**(Botany) 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.**(Mechanical Engineering) 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

[C16: from Latin: rod, ray, spoke]

## ra•di•us

(ˈreɪ di əs)*n.,*

*pl.*

**-di•i**(-diˌaɪ)

**-di•us•es.**

**1.**a straight line extending from the center of a circle or sphere to the circumference or surface:

*The radius of a circle is half the diameter.*

**2.**the length of such a line.

**3.**any radial or radiating part.

**4.**a circular area having an extent determined by the length of the radius from a given or specified central point: every house within a radius of 50 miles.

**5.**a field or range of operation or influence.

**6.**extent of possible operation, travel, etc., as under a single supply of fuel.

**7.**the bone of the forearm on the thumb side.

**8.**a corresponding bone in the forelimb of other vertebrates.

[1590–1600; < Latin: staff, rod, spoke, beam, ray

^{1}]## ra·di·us

(rā′dē-əs)*Plural*

**radii**(rā′dē-ī′)

*or*

**radiuses**

**1.**A line segment that joins the center of a circle or sphere with any point on the circumference of the circle or the surface of the sphere. It is half the length of the diameter.

**2.**The shorter and thicker of the two bones of the forearm or the lower portion of the foreleg. See more at skeleton.

## radius

One of the two bones of the forearm.

ThesaurusAntonymsRelated WordsSynonyms

**Legend:**Switch to new thesaurus

Noun | 1. | radius - the length of a line segment between the center and circumference of a circle or spherediam, diameter - the length of a straight line passing through the center of a circle and connecting two points on the circumference semidiameter - the apparent radius of a celestial body when viewed as a disc from the earth radius of curvature - the radius of the circle of curvature; the absolute value of the reciprocal of the curvature of a curve at a given point length - the linear extent in space from one end to the other; the longest dimension of something that is fixed in place; "the length of the table was 5 feet" |

2. | radius - a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)straight line - a line traced by a point traveling in a constant direction; a line of zero curvature; "the shortest distance between two points is a straight line" | |

3. | radius - a circular region whose area is indicated by the length of its radius; "they located it within a radius of 2 miles" | |

4. | radius - the outer and slightly shorter of the two bones of the human forearmforearm - the part of the superior limb between the elbow and the wrist arm bone - a bone in the arm | |

5. | radius - support consisting of a radial member of a wheel joining the hub to the rimbicycle wheel - the wheel of a bicycle cartwheel - a wheel that has wooden spokes and a metal rim support - any device that bears the weight of another thing; "there was no place to attach supports for a shelf" wagon wheel - a wheel of a wagon |

Translations

**نِصْف القُطر**

**poloměr**

**okruh**

**afstand**

**radius**

**säde**

**värttinäluu**

**hatósugár**

**radíus**

**geisli**

**polomer**

**polmer**

**yarı çap**

**yarı çap çizgisi**

## radius

*n pl*<radii>

(Math) → Radius

*m*, → Halbmesser*m*;*(of ship, aircraft)*→ Aktionsradius*m*, → Wirkungsbereich*m*; within a 6 km**radius**(of Hamburg) → in einem Umkreis von 6 km (von Hamburg)(Anat) → Speiche

*f*## radius

(ˈreidiəs)*noun*

**1.**(

*plural*

**ˈradiuses**) the area within a given distance from a central point. They searched within a radius of one mile from the school.

**2.**(

*plural*

**ˈradii**(-diai) ) a straight line from the centre of a circle to its circumference.

## ra·di·us

*n.*radio.

**1.**hueso largo del antebrazo;

**2.**línea recta que une el centro y cualquier punto de la circunferencia.

## radius

*n*(

*pl*

**radii**) radio

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