| Abbreviation | Definition |
|---|---|
| APEX | Apex Tank Car Line |
| APHX | Air Products Polymers |
| APIX | Allied Packers (Auriga Polymers) |
| APIX | Commonwealth Plan Incorporated |
| APJ | Arches Point Junction |
| APLU | American President Lines |
| APLU | American President Lines Limited |
| APLX | APL Land Transport Services |
| APLX | APL Land Transport Services Incorporated |
| APLZ | American President Lines |
| APLZ | American President Lines Limited |
| APMU | A.P. Moller (Maersk Lines) |
| APMU | Maersk Lines |
| APMX | Air Products Manufacturing |
| APMX | Air Products Manufacturing Company |
| APMZ | A.P. Moller (Maersk Lines) |
| APNC | Appanoose County Community Railroad |
| APOX | Alabama Power |
| APOX | Albama Power Company |
| APRX | Air Products and Chemicals |