logic gate

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

• noun A mechanical, optical, or electronic system that performs a logical operation on an input signal.

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

• noun a physical device, typically electronic, which computes a Boolean logical output (0 or 1) from Boolean input or inputs according to the rules of some logical operator.

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

• noun a computer circuit with several inputs but only one output that can be activated by particular combinations of inputs