| Keyword | Excerpt (click on keyword for complete article) |
| A# quenilla | Although it seems counterintuitive to a modern western musician, the "black key tuned" quenas are often referred to as tuned in sharp rather than flat keys. Thus the B flat quenilla becomes the A shar |
| A (1) | Note of the scale. A440 (440 cycles per second) is commonly used for tuning the orchestra. |
| A (2) | Abbreviation of alto. |
| A (3) | Abbreviation of (It.) anulare: "ring finger". Right hand fingering for the guitar. |
| A-banjo | See A-scale banjo. |
| A bass clarinet | Although the bass clarinet is usually tuned in Bb, there is also a variant tuned in A, a semitone ower. |
| A biffero | |
| A. Bord | Piano manufacturer in Paris. |
| A cane flute | |
| A cane whistle | |
| À capella | (It.) Singing without instrumental accompaniment. |
| A clarinet | A clarinet tuned in A, a semitone lower than the Bb clarinet and sounding a minor third below notated pitch. |
| A cornet | A cornet slightly larger than the regular Bb cornet and tuned in A. |
| A delingo | |
| A deux cordes | See À due corde. |
| A. di Mauro | Guitar manufacturer in Paris |
| A. Dieudonne fils | See Dieudonné, Amédée Dominique. |
| À due | Both instrument on the same part play (used after a solo section). |
| À due corde | (It., Fr.: "a deux cordes" or "deux cordes") "On two strings". Often shortened to just "due corde". In piano music this occasionally indicates the release of the soft pedal. |
| A flugelhorn | |
