radial

American  

[rey-dee-uhl] / ˈreɪ di əl /

adjective

1. arranged like radii or rays.

2. having spokes, bars, lines, etc., arranged like radii, as a machine.

3. made in the direction of a radius; going from the center outward or from the circumference inward along a radius.

   a radial cut.

4. Zoology. pertaining to structures that radiate from a central point, as the arms of a starfish.

5. of, like, or pertaining to a radius or a ray.

6. Machinery.

   1. having pistons moving inward and outward from a central point or shaft.

      a radial engine; a radial pump.

   2. noting a bearing designed primarily to take thrusts radial to the center of rotation.

7. Anatomy, Entomology. of, relating to, or situated near the radius.

8. acting along or in the direction of the radius of a circle.

   radial motion; radial velocity.

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noun

1. a radial section or construction.

2. Automotive. radial tire.

radial British  

/ ˈreɪdɪəl /

adjective

1. (of lines, bars, beams of light, etc) emanating from a common central point; arranged like the radii of a circle

2. of, like, or relating to a radius or ray

3. spreading out or developing uniformly on all sides

4. of or relating to the arms of a starfish or similar radiating structures

5. anatomy of or relating to the radius or forearm

6. astronomy (of velocity) in a direction along the line of sight of a celestial object and measured by means of the red shift (or blue shift) of the spectral lines of the object Compare tangential

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noun

1. a radial part or section

2. zoology

   1. any of the basal fin rays of most bony fishes

   2. a radial or radiating structure, such as any of the ossicles supporting the oral disc of a sea star

3. short for radial tyre radial drilling machine

Other Word Forms

• multiradial adjective
• radiality noun
• radially adverb

Etymology

Origin of radial

1560–70; < Medieval Latin radiālis, equivalent to Latin radi ( us ) beam, ray ( see radius) + -ālis -al ¹

Explanation

Radial things stick out from a center point or have to do with the radius of a circle. On a map, you can see that a traffic circle or roundabout consists of radial streets extending out from the center. A radius is a line from the center of a circle to its edge, or circumference. The adjective radial describes anything that acts as a radius or resembles one — often something radial is literally a line sticking straight out from a center point. Radial tires are designed so that each individual rubber cord making up the tire's surface lies in a radial direction from the middle of the tire. In Latin, radius means "shaft" or "spoke of a wheel."

Example Sentences

The playa is arranged as a semicircle, and radial streets are named as if their position were a clock face.

From Salon • Oct. 27, 2025

In addition to a rainbow of radial lasers, a brilliant column of light shoots into the sky, à la the Sacramento Kings’ beam.

From Los Angeles Times • Oct. 23, 2025

The four exoplanets, known as the sub-Earth exoplanets, were discovered using the radial velocity technique by the MAROON-X instrument.

From Space Scoop • Apr. 23, 2025

For the most recent study, the researchers joined TTV data with a radial velocity analysis of the star.

From Science Daily • Jan. 26, 2024

Years earlier, Beck had undergone a radial keratotomy* to correct his vision.

From "Into Thin Air" by Jon Krakauer