logic gate

American Heritage® Dictionary of the English Language, Fourth Edition

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

Wiktionary

1. n. 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.

WordNet 3.0

1. n. a computer circuit with several inputs but only one output that can be activated by particular combinations of inputs