| Abbreviation | Definition |
|---|---|
| MLIX | Melbo Land and Investment |
| MLKU | Matlack Leasing |
| MLLX | Montell USA (Basell USA) |
| MLLX | Montell USA Incorporated |
| MLMX | Morrison Grain (Metal Management) |
| MLR | Metro light rail |
| MLSU | Miller Intermodal Logistics Services |
| MLSX | Monsanto |
| MLSX | Monsanto Company |
| MLUX | Solutia |
| MLUX | Solutia Incorporated |
| MLW | Montreal Locomotive Works |
| MMA | Montreal, Maine and Atlantic Railway |
| MMA | Montreal, Maine, and Atlantic Railway |
| MMAC | Montreal, Maine and Atlantic Railway |
| MMAX | Martin Marietta Aluminum |
| MMAX | Martin Marietta Corporation |
| MMBX | Martin Marietta Corporation (Master Builders) |
| MMBX | Master Builders Incorporated |
| MMCU | CIE Des Messageries Maritimes |