| Abbreviation | Definition |
|---|---|
| MJ | More Jazz |
| MJA | Master Jazz Artist |
| MJB | Mary J. Blige |
| MJK | Maynard James Keenan, rock musician |
| MJO | Metropolitan Jazz Orchestra |
| MJQ | Manhattan Jazz Quintet |
| MJQ | Milt Jackson Quintet |
| MJQ | Modern Jazz Quartet |
| MJT | Modern Jazz Tuba |
| MJT | Modern Jazz Two |
| MJTKOP | Michael Jackson the King of Pop (fan site) |
| MJV | Maurice John Vaughn Band |
| MKF | Musical Kinematic Factory |
| MKLDF | Michael Kelly Legacy Dragonfly Flame (mandolin) |
| MKTO | My Kid Took Orchestra |
| ML | Music Literature |
| MLA | Mandated Lead Arranger |
| MLA | Music for Life Alliance |
| MLA | Music Library Association |
| MLAF | Music Lab Auditioning Facility |