steradianPronunciation: /stəˈreɪdɪən/ (abbreviation: sr)Definition of steradian noun 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. Origin: late 19th century: from Greek stereos 'solid' + radiansteradian in other Oxford dictionaries Definition of steradian in the US English dictionary
