SOLID

In Physics, the terra solid is applied to that condition of matter in which the attractive forces of the molecules are greater than the repulsive, and the molecules consequently cohere with greater or le force. The other states of matter are the fluid, in which the attractive and repulsive forces are balanced; and the gaseous, in which the repulsive prevail. Solid. In Geometry, a magnitude which has three dimensions; length, breadth, and thickne . The boundaries of solids are surfaces. Regular solids are those which are terminated by regular and equal planes. They are five in number, viz. the tetraedron, tiie hexaedron, the octaedron, the dodecaedron, and the icosaedron. See Platonic Bodies. SOLID ANGLE, in Geometry, is an angle made by the meeting of more than two plane angles which are not in the same plane in one point. [s. 1143]