square degree

A square degree (deg²) is a non-SI-compliant unit measure of solid angle. Other denotations include sq. deg. and (°)². Just as degrees are used to measure parts of a circle, square degrees are used to measure parts of a sphere. Analogous to one degree being equal to p / 180 radians, a square degree is equal to (p / 180)², or about 1 /  or 3.0462 steradian (0.30462 msr).