| S | Greek capital letter sigma; syphilis; summation of series |
|---|---|
| s | Greek lower case letter sigma; conductivity; cross section; millisecond; molecular type or bond; population standard deviation; stress; surface tension; wave number |
| S&A | sickness and accident [insurance]; sugar and acetone |
| S&C | sclerae and conjunctivae |
| S&E | safety and efficiency |
| S&H | speech and hearing |
| S&I | suction and irrigation |
| S&O | salpingo-oophorectomy |
| S&S | signs and symptoms |
| s-1 | cycles per second |