|—n , pl -dii, -diuses|
|1.||a straight line joining the centre of a circle or sphere to any point on the circumference or surface|
|2.||the length of this line, usually denoted by the symbol r|
|3.||the distance from the centre of a regular polygon to a vertex (long radius) or the perpendicular distance to a side (short radius)|
|4.||anatomy the outer and slightly shorter of the two bones of the human forearm, extending from the elbow to the wrist|
|5.||a corresponding bone in other vertebrates|
|6.||any of the veins of an insect's wing|
|7.||a group of ray florets, occurring in such plants as the daisy|
|8.||a. any radial or radiating part, such as a spoke|
|b. (as modifier): a radius arm|
|9.||the lateral displacement of a cam or eccentric wheel|
|10.||a circular area of a size indicated by the length of its radius: the police stopped every lorry within a radius of four miles|
|11.||the operational limit of a ship, aircraft, etc|
|[C16: from Latin: rod, ray, spoke]|
radius ra·di·us (rā'dē-əs)
n. pl. ra·di·us·es or ra·di·i (-dē-ī')
A line segment that joins the center of a circle with any point on its circumference.
A long, prismatic, slightly curved bone, the shorter and thicker of the two forearm bones, located laterally to the ulna.
|radius (rā'dē-əs) Pronunciation Key
Plural radii (rā'dē-ī') or radiuses
in anatomy, the outer of the two bones of the forearm when viewed with the palm facing forward. All land vertebrates have this bone. In humans it is shorter than the other bone of the forearm, the ulna.
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