Plane angle is suspended at a point in a plane by two converging straight lines and it magnitude is given by Solid angle is angel

$ω = area/radians^2$

Solid angle is angel generated by the surface passing through the point in space and the periphery of the area. Solid angle is denoted by ω expressed in stre radians and is given by the ratio of area of the surface to the square of the distance between the area and the point