| Name | Meaning | Gender | Origin |
|---|
| Rusty | Rusty, full of rust | Unisex | American English |
| Sabre | | Unisex | Hebrew |
| Sammy | His name is God | Unisex | Hebrew |
| Sarge | Noncommissioned Army or Air Force rank | Unisex | English |
| Sasha | Defending men | Unisex | Greek |
| Sassy | Lively and spirited | Unisex | English |
| Scooter | One who goes suddenly and speedily. | Unisex | English |
| Scout | Observer | Unisex | American English |
| Shadow | Shadow | Unisex | English |
| Shaggy | Bushy and matted (hair), unkempt. | Unisex | English |
| Shorty | Of less than average size | Unisex | English |
| Silly | | Unisex | Hebrew |
| Smoky | | Unisex | Hebrew |
| Socks | Short stockings finishing above the ankle | Unisex | English |
| Soda | A carbonated water. | Unisex | English |
| Sparky | Animated, lively. | Unisex | English |
| Spaz | For a spazy kitty | Unisex | English |
| Spot | After Data's cat on Star Trek: The Next Generation | Unisex | English |
| Sprite | Lemonade flavored soft drink. | Unisex | English |
| Squirt | Slang for a small person | Unisex | English |
| Stumpy | A short, thickset person | Unisex | English |
| Tango | | Unisex | Hebrew |
| Thunder | Stormy Tempered | Unisex | English |
| Tobey | God is good | Unisex | Hebrew |
| Toby | God is good | Unisex | Hebrew |
| Tootsie | A girl or young woman. | Unisex | English |
| Trooper | A state or mounted police officer. Also a member of a cavalry unit. | Unisex | English |
| Twiggy | | Unisex | Hebrew |
| Whiskey | An alcoholic liquor distilled from grain | Unisex | English |
| Winnie | Blessed peace | Unisex | Welsh |