The Collaborative International Dictionary
subsemitone
Subtonic \Sub*ton"ic\, n.
(Phonetics) A subtonic sound or element; a vocal consonant, as b, d, g, n, etc.; a subvocal.
(Mus.) The seventh tone of the scale, or that immediately below the tonic; -- called also subsemitone.
Wiktionary
subsemitone
n. (context music English) The sensible or leading note, or sharp seventh, of any key; subtonic.