SO3
| Acronym | Definition |
|---|---|
| SO3 | Sulfur Trioxide |
| SO3 | Sulfite (chemistry) |
| SO3 | Star Ocean 3 (game) |
| SO3 | Sons of the 3rd (band) |
| SO3 | Strategic Objective 3 |
| SO3 | Staff Officer 3 (various locations) |
| SO3 | Sonarman Third Class (former Naval Rating) |
| SO3 | Special Orthogonal Group in 3 dimensions |
| SO3 | Special Warfare Operator (Third Class) |