MACHINA, in the general, signifies any thing that serves to augment, or to regulate moving powers; or it is any body destined to produce motion, so as to save either time or force. The word comes from the Greek μηχάνη, "machine, invention, art." And hence, in strictness, a machine is something that consists more in art and invention, than in the strength and solidity of the materials; and for this reason it is that the inventors of machines are called ingenieurs or engineers.

Machines are either simple or compound. The simple ones are the seven mechanical powers, viz. lever, balance, pully, axis and wheel, wedge, screw, and inclined plane.

From these the compound ones are formed by various combinations, and serve for different purposes. See Machinery Mechanics and Hydrostatics; also the articles Centrifugal, Fire, Steam, Furnace, Burner, Roughs, Ramsden, &c.