Definition
(Noun) The use of more words in a sentence or clause than are necessary to express the meaning; redundancy of expression either as a fault of style, or as a rhetorical figure used for emphasis or clarity. Also: an instance of this; a superfluously worded expression or phrase.
In Context
“The term ‘digital computer’ is not a pleonasm: There are, in fact, analogue computers which, by their design, are not restricted to the digital representation of information.”
Thomas Riechmann, Learning in Economics: Analysis and Application of Genetic Algorithms, 2001.