The Collaborative International Dictionary of English v.0.48:

Gemination \Gem`i*na"tion\, n. [L. geminatio.]
   A doubling; duplication; repetition. [R.] --Boyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gemination
    n 1: the doubling of a word or phrase (as for rhetorical effect)
    2: the act of copying or making a duplicate (or duplicates) of
       something; "this kind of duplication is wasteful" [syn:
       duplication, gemination]