| genus suksdorfia | (n) small genus of rhizomatous herbs of northwestern America and South America |
| subularia | (n) small genus of herbs of north temperate regions and mountains of tropical Africa, Syn. genus Subularia |
| suillus | (n) a genus of fungi belonging to the family Boletaceae, Syn. genus Suillus |
| sula | (n) type genus of the Sulidae, Syn. genus Sula |
| sundacarpus | (n) one species, Syn. genus Sundacarpus |
| suricata | (n) meerkats, Syn. genus Suricata |
| surnia | (n) a genus of hawk-like owls, Syn. genus Surnia |
| sus | (n) type genus of the Suidae, Syn. genus Sus |