半径

(1)a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)

(2)円の中心から円周まで（または球の中心から球面まで）の直線

(3)a circular region whose area is indicated by the length of its radius; "they located it within a radius of 2 miles"

(4)半径の長さで示される円形の区域

(5)the length of a line segment between the center and circumference of a circle or sphere

(6)円または球の中心と円周の間の線分の長さ