A round solid figure, or its surface, with every point on its surface equidistant from its center. ;an area of activity, interest, or expertise; a section of society or an aspect of life distinguished and unified by a particular characteristic. Enclose in or as if in a sphere. Denoting a structure or region of spherical form, especially a region around the earth. Denoting an area of activity, section of society, etc., distinguished by a particular characteristic.