steradian

ste·ra·di·an  (st-rd-n)

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 4 steradians. See Table at measurement.

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[ste(reo)- + radian.]

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steradian [stəˈreɪdɪən]

n

(Mathematics & Measurements / 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

[from stereo- + radian]

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steradian  (st-rd-n)

A unitless measure of solid angles. A solid angle projecting from the center of a sphere and cutting its surface has a measure of ^s/_r² steradians, where s is the surface area of the sphere cut out by the solid angle, and r is the radius of the sphere. See also radian.

Thesaurus

Noun

1.

steradian - the unit of solid angle adopted under the Systeme International d'Unites sr angular unit - a unit of measurement for angles sphere - a three-dimensional closed surface such that every point on the surface is equidistant from the center