The Collaborative International Dictionary of English v.0.48:

Reduplicate \Re*du"pli*cate\ (r?*d?"pl?*k?t), a. [Pref. re- +
   duplicate: cf. L. reduplicatus. Cf. Redouble.]
   1. Double; doubled; reduplicative; repeated.
      [1913 Webster]

   2. (Bot.) Valvate with the margins curved outwardly; -- said
      of the ?stivation of certain flowers.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Reduplicate \Re*du"pli*cate\ (-k?t), v. t. [Cf. LL.
   reduplicare.]
   [1913 Webster]
   1. To redouble; to multiply; to repeat.
      [1913 Webster]

   2. (Gram.) To repeat the first letter or letters of (a word).
      See Reduplication, 3.
      [1913 Webster]

WordNet (r) 3.0 (2006):

reduplicate
    v 1: form by reduplication; "The consonant reduplicates after a
         short vowel"; "The morpheme can be reduplicated to
         emphasize the meaning of the word" [syn: reduplicate,
         geminate]
    2: make or do or perform again; "He could never replicate his
       brilliant performance of the magic trick" [syn: duplicate,
       reduplicate, double, repeat, replicate]