1. the use of more words than are necessary to express an idea; redundancy.
2. an instance of this, as free gift or true fact.
3. a redundant word or expression.
Origin: Pleonasm stems from the Late Latin noun pleonasmus, from the Greek pleonasmós “superabundance, excess,” in rhetoric “pleonasm,” from the Greek adjective pleíōn meaning “more.” It entered English in the early 1600s.
“PLEONASM, n. An army of words escorting a corporal of thought.” - Ambrose Bierce