Theory & harmony
Enharmonic
Two notes are enharmonic when they sound the same pitch but are written differently, such as F sharp and G flat.
On a piano the two are the same key, which makes enharmonic spelling look like a mere convention. On a string instrument it is not quite: players tune expressively, and a leading tone spelled as a sharp is often placed slightly higher than the same pitch spelled as a flat resolving downward. The spelling encodes the note's harmonic direction.
Composers choose the spelling that makes the harmony readable. A dominant chord resolving upward gets sharps; a chord borrowed from the parallel minor gets flats. When a piece modulates far from its home key, an enharmonic respelling is often what keeps the page legible.
Related terms
Every term in this glossary is taught in context somewhere in Arco's curricula, on the staff, on the keyboard, and on your own fingerboard at the same time.