Mus. [ad. med.L. subsemitonium: see SUB- 13.] The leading note of a scale.

1

c. 1800.  Busby, Dict. Mus., Sub-Semitone, the name by which theorists distinguish the sharp seventh, or sensible, of any key.

2

1876.  Stainer & Barrett, Dict. Mus. Terms.

3