There are all kinds of little known literary terms. I feel we (as writers) should know them, or at least carry a few up our sleeves to pull out and amaze others upon occasion. I ran into such a term (a word actually) on Dragon Writing Prompts.
Reduplication, in linguistics, is a morphological process by which the root or stem of a word, or part of it, is repeated. Definition from Wikipedia.
Some examples are: artsy-fartsy, razzle-dazzle, hobnob and hocus-pocus.