[rey-dee-uh l]
See more synonyms for radial on Thesaurus.com
  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.
  1. a radial section or construction.
  2. Automotive. radial tire.

Origin of radial

1560–70; < Medieval Latin radiālis, equivalent to Latin radi(us) beam, ray (see radius) + -ālis -al1
Related formsra·di·al·i·ty, nounra·di·al·ly, adverbmul·ti·ra·di·al, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for radial

spiral, branched, outspread, radiating, spoked

Examples from the Web for radial

Historical Examples of radial

British Dictionary definitions for radial


  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 objectCompare tangential (def. 2)
  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
Derived Formsradially, adverb

Word Origin for radial

C16: from Medieval Latin radiālis from radius
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

Word Origin and History for radial

c.1400, "of or like a ray or radius," from Medieval Latin radialis, from Latin radius "shaft, rod; spoke of a wheel; beam of light" (see radius). As a noun, a type of tire, attested from 1965, short for radial-ply (tire). Related: Radially.

Online Etymology Dictionary, © 2010 Douglas Harper

radial in Medicine


  1. Of, relating to, or near the radius or forearm.
  2. Moving or directed along a radius.
  3. Radiating from or converging to a common center.
Related formsradi•al•ly adv.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.