| Abbreviation | Definition |
|---|---|
| OM1 | ticalman Petty Officer 1st Class |
| OM2 | Opticalman Petty Officer 2nd Class |
| OM2 | ticalman Petty Officer 2nd Class |
| OM3 | Opticalman Petty Officer 3rd Class |
| OM3 | ticalman Petty Officer 3rd Class |
| OMC | Opticalman Chief Petty Officer |
| OMC | ticalman Chief Petty Officer |
| OMCM | Opticalman Master Chief Petty Officer |
| OMCM | ticalman Master Chief Petty Officer |
| OMCS | Opticalman Senior Chief Petty Officer |
| OMCS | ticalman Senior Chief Petty Officer |
| OMN | Operations Maintenance Navy |
| OMNR | Operation and Maintenance Navy Reserve |
| OMSA | Opticalman Seaman Apprentice |
| OMSA | ticalman Seaman Apprentice |
| OMSN | Opticalman Seaman |
| OMSN | ticalman Seaman |
| OMSR | Opticalman Seaman Recruit |
| OMSR | ticalman Seaman Recruit |
| ON | Old Navy |