tautonym

noun3

1. •
   A binomial name consisting of the same word twice, such as Bison bison.

   • And that would mean a species named Leucanthemum leucanthemum, with the genus and species epithet the same (a tautonym), which is a total no-no in botany. — 2013
2. •
   A word or term made from two identical parts or syllables, such as bonbon or dada.
3. •
   An absolute synonym.