steradian
/stəˈreɪdiən/
noun
- A unit for measuring solid angles in three-dimensional space, equal to the angle at the center of a sphere cut by a surface area equal to the square of the sphere's radius.
- In physics class, we learned how to calculate solid angles in steradians.
- The flashlight's beam covers only a few steradians of the total sphere.
- A full sphere measures about 12.57 steradians.