The SI unit of solid angle, equal to the angle at the centre 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.
Definition of steradian in:
- The US English dictionary