radius — ONAD

radius /ˈrādēəs, ˈreɪdiəs

▸ noun

(plural radii /ˈrādēˌī, ˈreɪdiˌaɪ

/ or radiuses)

1 a straight line from the center to the circumference of a circle or sphere. See also illustration at geometric.

▪ a radial line from the focus to any point of a curve.

▪ the length of the radius of a circle or sphere.

▪ a specified distance from a center in all directions:

there are plenty of local pubs within a two-mile radius.

2 Anatomy the thicker and shorter of the two bones in the human forearm. Compare with ulna.

▪ Zoology the corresponding bone in a vertebrate's foreleg or a bird's wing.

▪ Entomology any of the main veins in an insect's wing.

3 Zoology (in an echinoderm or coelenterate) any of the primary axes of radial symmetry.

▸ verb

(radiuses, radiusing, radiused)

[with object] give a rounded form to (a corner or edge):

Brian carefully radiused all the sharp edges and corners

(as adjective radiused) the radiused edges feel sleek and unobtrusive in the hand.

– ORIGIN late 16th century (in radius (SENSE 2 OF THE noun)): from Latin, literally ‘staff, spoke, ray’.