| Abbreviation | Definition |
|---|---|
| STO | Store |
| STOS | Store String |
| STOSB | Store String Byte |
| STOSD | Store String Doubleword |
| STOSW | Store String Word |
| STR | Store Task Register |
| STRC | Stop Real-Time Clock |
| STREX | STore Register EXclusive |
| STROM | Store in Read-only Memory |
| STSN | Set and Test Sequence Numbers |
| STZ | Set Zero |
| SU | Stand Up |
| SU | Substitue User |
| SU | Substitute User |
| SU | Switch User |
| SU | Switch Users |
| SU | Syntax Unit |
| SUB | Subtract |
| SV | Save Video |
| SV | Scalar Value |