| Abbreviation | Definition |
|---|---|
| SA | Saturday |
| SAD | Single Awareness Day |
| SAD | Socrates Action Day |
| SAD | Swallow Arrival Day |
| SAT | Saturday |
| SD | Stepfamily Day |
| SIAD | Self Injury Awareness Day |
| SM | Saturday Morning |
| SO | SOnntag |
| SORR | Stay On Red Rocks |
| SRD | State Recognition Day |
| SS | Saturday, Sunday |
| SSN | Saturdays, Sundays, and Nights |
| STRESS | Senseless Turmoil Removing Emotional Sensible Solutions |
| SU | Sunday |
| SUN | Sunday |
| TAOS | Take Advance Of Something |
| TBD | The Big Day |
| TDY | Today |
| TED | Tired Engineers Day |