释义 |
steradian Geom.|stəˈreɪdɪən| [f. Gr. στερεός solid + radian n.] A unit of measurement of solid angles (see quot. 1881).
1881Halsted Mensuration 78 A steradian is the angle subtended at the center by that part of every sphere equal to the square of the radius. 1883W. Thomson in Encycl. Brit. XVI. 25/2 Number of Steradians in an Angle. 1885A. Macfarlane Phys. Arith. 87 The unit-rate S per (L radius)2 is sometimes called a steradian, that is, a solid radian. |