generator

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that generates, especially a machine that converts mechanical energy into electrical energy.
• noun An apparatus that generates vapor or gas.
• noun A circuit that generates a specified waveform.
• noun Computers A program that produces specific programs from the definition of an operation.

from The Century Dictionary.

• noun One who or that which begets, causes, or produces.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who, or that which, generates, begets, causes, or produces.
• noun 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.
• noun (Mus.) The principal sound or sounds by which others are produced; the fundamental note or root of the common chord; -- called also generating tone.
• noun (Elec.) Any machine that transforms mechanical into electrical energy; a dynamo.
• noun (Math.) a mathematical entity which, when subjected to an operation, yields another mathematical entity; also, a generatrix.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One who, or that which, generates, begets, causes, or produces.
• noun A piece of apparatus, equipment, etc, to convert or change energy from one form to another.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an electronic device for producing a signal voltage
• noun an apparatus that produces a vapor or gas
• noun someone who originates or causes or initiates something
• noun engine that converts mechanical energy into electrical energy by electromagnetic induction