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View synonyms for

radius

[ rey-dee-uhs ]

noun

plural radii radiuses.
  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:

    the flying radius of an airplane.

  7. Anatomy. the bone of the forearm on the thumb side. Compare ulna ( def 1 ).
  8. Zoology. a corresponding bone in the forelimb of other vertebrates.
  9. Machinery Now Rare. the throw of an eccentric wheel or cam.
  10. a rounded corner or edge on a machined or cast piece of metal.
  11. Entomology. one of the principal longitudinal veins in the anterior portion of the wing of an insect.


radius

/ ˈɪɪə /

noun

  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
    1. any radial or radiating part, such as a spoke
    2. ( as modifier )

      a radius arm

  8. the lateral displacement of a cam or eccentric wheel
  9. a circular area of a size indicated by the length of its radius

    the police stopped every lorry within a radius of four miles

  10. the operational limit of a ship, aircraft, etc
“Collins English Dictionary — Complete & Unabridged” 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

radius

  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.
  3. See more at skeleton
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Word History and Origins

Origin of radius1

First recorded in 1590–1600; from Latin: “staff, rod, spoke, beam,” originally, “ray”; ray 1
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Word History and Origins

Origin of radius1

C16: from Latin: rod, ray, spoke
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Example Sentences

Examples have not been reviewed.

With no imminent danger within our radius, he returns to Joe’s final words.

From

We mixed each property’s soil — collected from four inches deep in multiple spots within a five- to 10-foot radius — in a plastic bag.

From

"The radius should be put on them. So we know where they are and we have the freedom of the UK."

From

There is only one beach patrolled by lifeguards within a 50-kilometre radius of Seventeen Seventy.

From

The buffer zones, prohibit protest, within a 150-metre radius around abortion services and those convicted of breaking the law could face an unlimited fine.

From

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