Generator

Part of speech: noun (n.)

1. One who, or that which, generates, begets, causes, or produces.

2. An apparatus in which vapor or gas is formed from a liquid or solid by means of heat or chemical process, as a steam boiler, gas retort, or vessel for generating carbonic acid gas, etc.

3. The principal sound or sounds by which others are produced; the fundamental note or root of the common chord; -- called also generating tone.