| Name | Meaning | Gender | Origin |
|---|
| Smudge | A blotch or smear | Male | |
| Snickers | A brand of candy bar. | Unisex | |
| Snickers | A brand of candy bar. | Unisex | |
| Snowball | | Unisex | |
| Snuggles | To curl up closely, cuddle | Male | |
| Snuggles | To curl up closely, cuddle | Male | |
| Socks | Short stockings finishing above the ankle | Unisex | |
| Sonny | A boy or young man. | Male | Nickname |
| Sooty | Covered with soot | Unisex | |
| Sophia | Wisdom.
| Female | Greek |
| Sophie | Wisdom. Variant of Sophia
| Female | |
| Sox | Short stockings finishing above the ankle | Unisex | |
| Sox | Short stockings finishing above the ankle | Unisex | |
| Spencer | Shopkeeper, dispenser, keeper | Male | English |
| Spike | A long, thick sharp-pointed piece of wood or metal | Male | American |
| Spooky | | Unisex | |
| Stella | a star | Female | Latin |
| Stella | a star | Female | Latin |
| Sugar | A sweet powder from sugar cane. Slang for sweetheart. | Female | Literary |
| Sugar | A sweet powder from sugar cane. Slang for sweetheart. | Female | Literary |
| Sunny | Abounding in sunshine, cheerful | Male | Nickname |
| Susi | | Unisex | Hebrew |
| Suzy | Lily | Unisex | English |
| Sweetie | Sweetheart. | Male | |
| Swiss Miss | | Unisex | |