| sionismo | Zionism |
| Sionismo cristiano | Christian Zionism |
| Sionismo revisionista | Revisionist Zionism |
| Sionismo socialista | Labor Zionism |
| sionista | Zionist |
| sip | yep |
| Sipahi | Sipahi |
| Sipaliwini | Sipaliwini District |
| Siphonaptera | Flea |
| Siphonophora | Siphonophora |
| Sipoo | Sipoo |
| SIPP | SIPP memory |
| Sippar | Sippar |
| Sippe | Band society |
| Siptah | Siptah |
| Sipuncula | Sipuncula |
| Siquem | Shechem |
| siquiatra | alienist |
| siquiatría | psychiatry |
| siquiera | at least |
| Siquis | Psyche |
| siquiátrico | psychiatric |
| Sir | Sir |
| Sir Daria | Syr Darya |
| Sir Gawain y el Caballero Verde | Sir Gawain and the Green Knight |
| Sir Héctor | Sir Ector |
| Sir Kay | Sir Kay |
| Sir Leigh Teabing | Leigh Teabing |
| Sir Lionel | Sir Lionel |
| Sir Mix-a-Lot | Sir Mix-a-Lot |
| Siracusa | Syracuse |
| Sirajganj | Sirajganj |
| Sirdarín | Sirdaryo Province |
| Siren lacertina | Greater Siren |
| sirena | mermaid |
| sirena de niebla | foghorn |
| Sirenia | Sirenia |
| Sirenidae | Siren |
| sirga | towrope |
| Sirhan Bishara Sirhan | Sirhan Sirhan |
| Siria | Syria |
| Siricio | Pope Siricius |
| Siricio I | Pope Siricius |
| Sirikit Rajini | Sirikit |
| Sirimavo Bandaranaike | Sirimavo Bandaranaike |
| siringomielia | syringomyelia |
| sirio | Syrian |
| sirirí | whistling duck |
| Sirius Black | Sirius Black |
| Sirmia | Syrmia |
| Sirmio | Sirmium |
| siroco | sirocco |
| sirope | syrup |
| Siros | Syros |
| Sirrush | Sirrush |
| Sirtaki | Sirtaki |
| Sirusho Harutyunyan | Sirusho |
| Sirventés | Sirventes |
| sirvienta | attendant |
| sirviente | attendant |
| sisa | armhole |
| Sisak | Sisak |
| sisal | sisal |
| sisar | steal |
| sisear | hiss |
| Sisebuto | Sisebut |
| Siselen | Siselen |
| Sisenando | Sisenand |
| siseo | hiss |
| Sisikon | Sisikon |
| Sisino | Pope Sisinnius |
| Sisitia | Syssitia |
| sismo | quake |
