Definition of: epenthesis

(ep·en′thə·sis) noun plural ·ses (-sēz)
1. The intrusion of a letter or syllable within a word, as the d in thunder (Old English thunor).
2. The phonetic change resulting from the transference of a semivowel to the syllable preceding, as (in the Greek) in changing karjo to kairo. [<LL <Gk. <epi- upon + en- in + tithenai place]
—ep·en·thet·ic (ep′·en·thet′ik) adjective