The Collaborative International Dictionary of English v.0.48:

Aphonia \A*pho"ni*a\, Aphony \Aph"o*ny\, n. [NL. aphonia, Gr. ?,
   fr. ? voiceless; 'a priv. + ? voice: cf. F. aphonie.] (Med.)
   Loss of voice or vocal utterance.
   [1913 Webster] Aphonic