Of or pertaining to a ray or a radius (or radii); having the character or appearance of a ray or a radius; grouped or appearing like radii or rays; shooting out as from a center; being or moving in the direction of the radius.Specifically— In anatomy, of or pertaining in any way to the radius (see radius, 2): as, the radial artery, nerve, vein; radial articulations or movements; the radial side or aspect of the arm, wrist, or hand; the radial group of muscles; the radial pronator or supinator.In zoology, rayed, radiate, or radiating; of or pertaining to the rays, arms, or radiating processes of an animal; relating to the radially disposed or actinomeric parts of the Radiata and similar animals. See cut under medisiform.In ichthyology, of or pertaining to the radialia. See radiale .In botany:Belonging to a ray, as of an umbel or of a flower-head in the Compositæ.Developing uniformly on all sides of the axis: opposed to bifacial or dorsiventral.n. A radiating or radial part: a ray.n. The fourth joint, counting from the base, of the pedipalp of a spider.n. In ichthyology, one of the cartilaginous rays supporting the median fins of elasmobranchs.