Solid, in mathematics, is a geometric figure with the three dimensions of length, breadth, and thickness. Some solids are named from the shapes of their surfaces, such as cubes, cylinders, cones, and spheres. In physics, solid refers to one of the three basic states (forms) in which matter may exist. The other states are liquid and gaseous. The state of each body of matter is classified according to the power of its molecules to resist forces that may change its shape. A solid has a fixed shape and volume because its molecules cannot move freely.
