| 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) |