The Collaborative International Dictionary of English v.0.48:

Pleonasm \Ple"o*nasm\,, n. [L. pleonasmus, Gr. ?, fr. ? to be
   more than enough, to abound, fr.?, neut. of ?, more, compar.
   of ? much. See Full, a., and cf. Poly-, Plus.] (Rhet.)
   Redundancy of language in speaking or writing; the use of
   more words than are necessary to express the idea; as, I saw
   it with my own eyes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pleonasm
    n 1: using more words than necessary; "a tiny little child"

The Free On-line Dictionary of Computing (30 December 2018):

pleonasm

   Redundancy of expression; tautology.

   (1995-03-25)


The Devil's Dictionary (1881-1906):

PLEONASM, n.  An army of words escorting a corporal of thought.