Definition of steradian in English:


Syllabification: ste·ra·di·an
Pronunciation: /stəˈrādēən
(abbreviation: sr)


  • The SI unit of solid angle, equal to the angle at the center of a sphere subtended by a part of the surface equal in area to the square of the radius.
    More example sentences
    • A sphere subtends 4 pi square radians (steradians) about the origin.
    • There are also two supplementary units, the radian, and the steradian.
    • This is the power of the light that is emitted per projected surface area into a given solid angle, and it is measured in watts per square metre per steradian.


late 19th century: from Greek stereos 'solid' + radian.

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