a straight line extending from the centre of a circle or sphere to the circumference or surface, or the length of this line
a radial part, e.g. a spoke of a wheel
the circular area defined by a stated radius
all traffic within a two-mile radius
a bounded or circumscribed area
the bone on the thumb side of the human forearm, or a corresponding part in other forms of vertebrate animals higher than fishes: compare ulna
the third and usu largest vein of an insect's wing
an imaginary radial plane dividing the body of a radially symmetrical animal, e.g. a starfish, into similar parts
[Latin radius ray1, radius]