Radial  —adj. 1 of or in rays. 2 a arranged like rays or radii. B having spokes or radiating lines. C acting or moving along lines diverging from a centre. 3 (in full radial-ply) (of a tyre) having fabric layers arranged radially and the tread strengthened. —n. Radial-ply tyre.  radially adv. [medieval latin: related to *radius]