| Abbreviation | Definition |
|---|---|
| MSCI | Mississippi Central Railroad Company |
| MSCU | Mediterranean Shipping |
| MSCU | Mediterranean Shipping Company |
| MSCZ | Mediterranean Shipping |
| MSCZ | Mediterranean Shipping Company |
| MSDR | Mississippi Delta Railroad |
| MSE | Mississippi Export Railroad |
| MSE | Mississippi Export Railroad Company |
| MSEX | Mountain States Energy Corp (Tour Alaska Inc. dba Princess Tours) |
| MSIX | Morton International |
| MSIX | Morton International Incorporated |
| MSL | Montgomery Short Line |
| MSLC | Minnesota Short Lines |
| MSMR | Madras and Southern Mahratta Railway |
| MSMX | Mid South Milling |
| MSN | Meeker Southern Railroad |
| MSO | Michigan Southern Railroad |
| MSO | Michigan Southern Railroad Incorporated |
| MSPX | P4 Production |
| MSPX | P4 Productions L. L. C. |