Definition of "subtonic"

(phonetics, dated) Of or pertaining to imperfectly articulated sounds or utterances that are inaudible or barely audible, as characterized by Dr. James Rush (Guide to Pronunciation, 1833).  examples

(music) The note immediately below the upper note of a musical scale.  examples

(phonetics, dated) An imperfectly articulated sound or utterance, as characterized by Dr. James Rush (Guide to Pronunciation, 1833).  examples