Cube (Gr. a die), in geometry, a solid body terminated by six square equal faces; occupying among bodies a place analogous to that of the square among surfaces. The problem of the duplication of the cube, or of constructing a cube of twice the volume of a given cube, is celebrated in the history of science. It occupied geometers in the time of Plato; and it was a Greek tradition that once during a pestilence the priestess at Delos had responded that in order to appease the gods her altar must be doubled. The altar was cubical, and a new one was built whose sides were of twice the dimensions of the old one. The priestess responded that her command had been wrongly interpreted, and from that time the geometrical duplication of cubic figures was a constant problem, like the quadrature of the circle. The cubature of solids, or the reduction of any body to a cubic form of equal volume, is performed by first reducing the given volume to one of the geometrical figures the law of whose curvature is known, as the parallelopipedon, cylinder, cone, or sphere. - In arithmetic and algebra, a cube is a number formed by raising another number to its third power; thus, 27 is the cube of 3, being equal to 3x3x3. The number which is thus multiplied to make a cube is called the cube root.