superfluous repetition or overlapping, especially of words.
a redundant thing, part, or amount; superfluity.
the provision of additional or duplicate systems, equipment, etc., that function in case an operating part or system fails, as in a spacecraft.
Linguistics. the inclusion of more information than is necessary for communication, as in those cars, where both words are marked for plurality. the additional, predictable information so included. the degree of predictability thereby created.