The prefix cyber- was first used in 1948 by Norbert Wiener (1894-1964), an American mathematician, when he coined the term cybernetics in his book of that title:
We have decided to call the entire field of control and communication theory, whether in the machine or in the animal, by the name Cybernetics.
Wiener based it on the Greek kubernetes, or steersman, which is also the root of the word govern. Wiener may also have based his word on an 1830s French usage of cybernétique, which meant the art of governing, but whether he took it directly from the Greek root or was familiar with the French term is unknown.
(Source: Oxford English Dictionary, 2nd Edition)
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