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Noun: a device used for transmitting and receiving messages
instantaneously over distances measuring in the hundreds of
light years.

This term was invented by science fiction novelist Ursula K.
LeGuin in the mid-1960's and first used in her novel
Rocannon's World. While this device is imaginary, it is a
term that has come to be widely used by science fiction
writers to refer to faster-than-light communication.