An electronic logic gate whose output is logic 1 (true) only when all (two or more) inputs are logic 0 (false), otherwise it is logic 0. It thus implements the logical NOR operation and has the same truth table. The diagram shows the usual circuit symbol of a two-input gate (which implies by the small circle that it is an inclusive OR gate whose output has been inverted) and the associated truth table. See also exclusive-NOR gate.
NOR gate. Two-input NOR gate, circuit symbol and truth table