| Syd Barrett | Syd Barrett |
| Sydenham's chorea | corea de Sydenham |
| Sydney | Sídney |
| Sydney Brenner | Sydney Brenner |
| Sydney FC | Sydney Football Club |
| Sydney Harbour Bridge | Puente del puerto de Sídney |
| Sydney Olympic FC | Sydney Olympic Football Club |
| Sydney Opera House | Ópera de Sídney |
| Sydney Pollack | Sydney Pollack |
| Sydney racial violence continues | Disturbios raciales en la ciudad de Sydney |
| Sydney Swans | Sydney Swans Football Club |
| Sydney Tamiia Poitier | Sydney Poitier |
| Sydney to Hobart Yacht Race | Regata Sydney-Hobart |
| Syens | Syens |
| Sykes-Picot Agreement | Acuerdos Sykes-Picot |
| Syktyvkar | Syktyvkar |
| Syldavia | Syldavia |
| Syldavian | Idioma syldavo |
| Sylhet | Sylhet |
| Sylhet Division | Sylhet |
| syllabic | silábico |
| syllable | sílaba |
| Syllable rime | Rima |
| Syllable weight | Longitud de arco |
| syllabub | manjar de leche y licores |
| syllabus | programa |
| Syllabus of Errors | Syllabus |
| syllogism | silogismo |
| Sylvain Wiltord | Sylvain Wiltord |
| sylvan | selvático |
| Sylvanus Morley | Sylvanus Morley |
| Sylvester | Silvestre |
| Sylvester James | Sylvester |
| Sylvester Medal | Sylvester Medal |
| Sylvester Shyster | Lupus |
| Sylvester Stallone | Sylvester Stallone |
| Sylvia | Sylvia |
| Sylvia Nasar | Sylvia Nasar |
| Sylvia Plath | Sylvia Plath |
| Sylvia Scarlett | La gran aventura de Silvia |
| Sylvie Vartan | Sylvie Vartan |
| Sylvinho | Sylvio Mendes Campos Junior |
| sym- | sim- |
| Symantec | Symantec |
| Symbian Ltd | Symbian |
| Symbian OS | Symbian OS |
| Symbionese Liberation Army | Ejército Simbiótico de Liberación |
| symbiont | simbionte |
| symbiosis | simbiosis |
| symbiotic | simbiótico |
| Symbiotic nova | Nova simbiótica |
| Symbiotic star | Estrella simbiótica |
| symbol | emblema |
| symbolic | simbólico |
| Symbolic Capital | Capital social |
| Symbolic interactionism | Interaccionismo simbólico |
| Symbolic link | Enlace simbólico |
| symbolically | simbólicamente |
| symbolise | simbolizar |
| symbolism | simbolismo |
| symbolize | representar |
| symbology | simbología |
| Symi | Sime |
| Symmachus | Símaco |
| symmetric | simétrico |
| Symmetric multiprocessing | Multiprocesamiento simétrico |
| Symmetric polynomial | Polinomios simétricos |
| Symmetric-key algorithm | Criptografía simétrica |
| symmetrical | simétrico |
| symmetrically | simétricamente |
| symmetry | simetría |
| Symon Petliura | Symon Petlyura |
| Symon Petlura | Symon Petlyura |
| sympathetic | simpático |
| Sympathetic magic | Magia simpática |
| sympathetic nervous system | sistema nervioso simpático |
| sympathies | pésame |
| sympathize | compadecerse de |
| sympathize with | tener lástima a |
| sympathizer | partidaria |
| Sympathomimetic amine | Amina simpaticomimética |
| sympathy | afinidad |
| Sympatric speciation | Especiación simpátrida |
| Symphonia | Zanfona |
| symphonic | sinfónico |
| Symphonic black metal | Symphonic black metal |
| Symphonic metal | Symphonic metal |
| Symphonic rock | Rock sinfónico |
| Symphonie | Sinfonía |
| Symphonie fantastique | Sinfonía fantástica |
| symphony | sinfonía |
| symphony orchestra | orquesta sinfónica |
| Symphony X | Symphony X |
| Symphoricarpos | Symphoricarpos |
| Symplectic manifold | Topología simpléctica |
| Symplegades | Estrecho de Cinadea |
| Symplesiomorphy | Simplesiomorfia |
| symposium | conferencia |
| symptom | síntoma |
| symptomatic | sintomático |
| symptomatology | semiología |
| Syn addition | Adición anti |
| Syn and Anti addition | Adición anti |
| synagogue | sinagoga |
| Synagogue of El Transito | Sinagoga del Tránsito |
| synalepha | sinalefa |
| Synapomorphy | Sinapomorfia |
| synapse | sinapsis |
| Synapsida | Mammalia |
| Synaptic Package Manager | Synaptic |
| Synaptic plasticity | Neuroplasticidad |
| Synaptic vesicle | Vesícula sináptica |
| Synarchism | Sinarquía |
| Syncarpha | Heliopsis |
| synch | sincronizar |
| synchrocyclotron | sincrociclotrón |
| synchromesh | cambio sincronizado |
| synchronised swimming | nado sincronizado |
| synchronization | sincronización |
| synchronize | sincronizar |
| Synchronized Multimedia Integration Language | SMIL |
| synchronous | sincrónico |
| Synchronous optical networking | SONET |
| Synchronous rotation | Rotación síncrona |
| synchrotron | sincrotrón |
| Synchrotron radiation | Radiación sincrotron |
| syncopate | sincopar |
| syncopation | síncopa |
| syncope | síncopa |
| syndesmosis | sindesmosis |
| syndical | sindical |
| syndicalism | sindicalismo |
| syndicalist | sindicalista |
| syndicate | sindicato |
| syndrome | síndrome |
| synecdoche | sinécdoque |
| synecology | sinecología |
| synergistic | sinergético |
| Synesius | Sinesio de Cirene |
| Synesthesia | Sinestesia |
| Syngman Rhee | Syngman Rhee |
| Syngnathidae | Syngnathidae |
| Syngnathiformes | Syngnathiformes |
