Machina, in 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 Machinery either time or force. The word comes from the Greek μηχανή, 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, for which reason inventors of machines are called ingénieurs, or engineers. Machines are either simple or compound. The simple ones are the seven mechanical powers, namely, the lever, balance, pulley, axis and wheel, wedge, screw, and inclined plane. See Mechanics.