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Related to steradian: candela
If A = r2 then solid angle Ω = 1 sr.
n. Abbr. sr
A unit of measure equal to the solid angle subtended at the center of a sphere by an area on the surface of the sphere that is equal to the radius squared. The total solid angle of a sphere is 4π steradians.
(Units) an SI unit of solid angle; the angle that, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to the square of the length of the radius. Symbol: sr
[C19: from stereo- + radian]