re·du·pli·cate 
(r
ĭ-d
pl
ə-k
āt
′, -dy
-)
v. re·du·pli·cat·ed, re·du·pli·cat·ing, re·du·pli·cates
v.tr.1. To repeat over and again; redouble.
2. Linguistics a. To double (the initial syllable or all of a root word) to produce an inflectional or derivational form.
b. To form (a new word) by doubling all or part of a word.
[Late Latin reduplicāre, reduplicāt- : Latin re-, re- + Latin duplicāre, to duplicate; see DUPLICATE.]