| SIA | Sia |
| Siad Barre | Siad Barre |
| Siad Most | FK SIAD Most |
| SIAI Marchetti | Savoia-Marchetti |
| Siaka Stevens | Siaka Stevens |
| Siaka Tiéné | Siaka Tiéné |
| Sialk | Tappeh Sialk |
| Sialkot | Sialkot |
| Siam | Thailand |
| Siamois | Siamese |
| Siamoise | Siamese |
| Siamon | Siamun |
| Siamosaure | Siamosaurus |
| Siarhieï Sidorski | Sergey Sidorsky |
| Siarnaq | Siarnaq |
| Siat | Siat |
| Sibaviatrans | Sibaviatrans |
| Sibač | Sibač |
| Sibel Kekilli | Sibel Kekilli |
| Sibel Tüzün | Sibel Tüzün |
| Sibenik | Sibenik |
| Siberut | Siberut |
| Sibir | Siberia Khanate |
| Sibir Novossibirsk | HC Sibir Novosibirsk |
| Sibiu | Sibiu |
| Siblingen | Siblingen |
| Sibu | Sibu |
| Sibutramine | Sibutramine |
| sibylle | sibyl |
| Sibylle de Jérusalem | Sibylla of Jerusalem |
| sibyllin | esoteric |
| Sibérie | Siberia |
| Sibérien | Siberian |
| Sibérienne | Siberian |
| sic | sic |
| Sicaires | Sicarii |
| Sicambres | Sicambri |
| Sicanes | Sicani |
| Sicco Leendert Mansholt | Sicco Mansholt |
| Sicherheitsdienst | Sicherheitsdienst |
| Sicherheitspolizei | Sicherheitspolizei |
| Sichuan | Sichuan |
| Sicile | Sicily |
| sicilien | Sicilian |
| Sicilienne | Sicilian |
| Siciste de bouleau | Northern Birch Mouse |
| Sicistinae | Birch mouse |
| Sick of it All | Sick of It All |
| Sick puppies | Sick Puppies |
| sicle | shekel |
| Sicules | Sicels |
| Sicules de Transylvanie | Székely |
| Sicyone | Sicyon |
| SID | MOS Technology SID |
| Sid et Nancy | Sid and Nancy |
| Sid Eudy | Sid Eudy |
| Sid Meier | Sid Meier |
| Sid Vicious | Sid Vicious |
| Sid Wilson | Sid Wilson |
| sida | AIDS |
| Siddharta | Siddhartha |
| Siddhi | Siddhi |
| Siddour | Siddur |
| side-car | side car |
| Side-project | Side project |
| Sidecar | Motorcycle combination |
| Sideritis | Sideritis |
| Siderostat | Siderostat |
| Sidh | Sídhe |
| Sidi Bou Saïd | Sidi Bou Said |
| Sidi Bouzid | Sidi Bou Zid |
| Sidi Mohamed Ould Boubakar | Sidi Mohamed Ould Boubacar |
| Sidi Mohamed Ould Cheikh Abdallahi | Sidi Ould Cheikh Abdallahi |
| Sidi-Bel-Abbès | Sidi Bel Abbes |
| Sidney Big Sid Catlett | Sid Catlett |
| Sidney Camm | Sydney Camm |
| Sidney Crosby | Sidney Crosby |
| Sidney Gilchrist Thomas | Sidney Gilchrist Thomas |
| Sidney Poitier | Sidney Poitier |
| Sidney Reilly | Sidney Reilly |
| Sidney Sheldon | Sidney Sheldon |
| Sidney Smith | William Sidney Smith |
| Sidoine Apollinaire | Sidonius Apollinaris |
| Sidon | Sidon |
| Sidé | Side |
| sidéral | sidereal |
| sidération | consternation |
| sidérer | stupefy |
| Sidérien | Siderian |
| Sidérophore | Siderophore |
| sidéré | dazed |
| Sidónio Pais | Sidónio Pais |
| Siebenlehn | Siebenlehn |
| Siebenrockiella crassicollis | Siebenrockiella crassicollis |
| Siedenburg | Siedenburg |
| Siedlce | Siedlce |
| Siegbahn | X unit |
| Siegbert Tarrasch | Siegbert Tarrasch |
| Siegen | Siegen |
| Siegen-Wittgenstein | Siegen-Wittgenstein |
| Siegessäule | Berlin Victory Column |
| Siegfried | Siegfried |
| Siegfried Held | Sigfried Held |
| Siegfried Kracauer | Siegfried Kracauer |
| Siegfried Lenz | Siegfried Lenz |
| Siegfried Wagner | Siegfried Wagner |
| Siegmar | Siegmar |
| Siegmund | Sigismund |
| Siegsdorf | Siegsdorf |
| Siem Reap | Siem Reap |
| Siemens | Siemens |
| Siemens AG | Siemens AG |
| Siemens IT Solutions and Services | Siemens IT Solutions and Services |
| Siemomysł | Siemomysł |
| Siemomysł de Poméranie | Siemomysł of Pomerania |
| Siemovit | Siemowit |
| Siemovit III de Mazovie | Siemowit III of Masovia |
| Siena | Siena |
| Sienna Guillory | Sienna Guillory |
| Sienna Miller | Sienna Miller |
| Sienne | Siena |
| Siennes | Kernel |
| siennois | Sienese |
| siennoise | Sienese |
| siens | home front |
| Sieradz | Sieradz |
| sierain | nostril |
| sierra | sierra |
| Sierra Club | Sierra Club |
| Sierra de Guadarrama | Sierra de Guadarrama |
| Sierra Leone | Sierra Leone |
| Sierra Madre del Sur | Sierra Madre del Sur |
| Sierra Madre Occidentale | Sierra Madre Occidental |
| Sierra Madre Orientale | Sierra Madre Oriental |
| Sierra Morena | Sierra Morena |
| Sierra Nevada | Sierra Nevada |
| Sierre | Sierre |
| sieste | siesta |
| Sieste éclair | Power nap |
| Sietch | Sietch |
| Siete Aguas | Siete Aguas |
| Sieur | Pan |
| sievert | sievert |
| Siewierz | Siewierz |
| Sif | Sif |
| Sifaka | Sifaka |
| SIFE | SIFE |
| sifflant | sibilant |
| sifflante | sibilant |
| sifflement | whizz |
| sifflement gras | wheeze |
| siffler | guzzle |
| sifflet | whistle |
| siffloter | whistle |
| Sifnos | Sifnos |
| sifu | sifu |
| SIG | geographic information system |
| Siganus vulpinus | Foxface rabbitfish |
| SIGARMS | SIG SAUER |
| Sigeberht | Sigeberht of Wessex |
| Sigebert | Sigebert |
| Sigebert de Gembloux | Sigebert of Gembloux |
| Sigebert Ier | Sigebert I |
| Sigebert II | Sigebert II |
| Sigebert III | Sigebert III |
| Sigebert le Boiteux | Sigobert the Lame |
| Sigefroy de Luxembourg | Siegfried of Luxembourg |
| Siger de Brabant | Siger of Brabant |
| Sigfrid Edström | Sigfrid Edström |
| Siggraph | SIGGRAPH |
| Sighetu Marmaţiei | Sighetu Marmaţiei |
| Sighişoara | Sighişoara |
| sigillographie | sigillography |
| Sigirino | Sigirino |
| Sigirîya | Sigiriya |
| sigisbée | beau |
| Sigismond | Sigismund of Burgundy |
| Sigismond Ier Báthory | Sigismund Báthory |
| Sigismond Ier de Pologne | Sigismund I the Old |
| Sigismond II de Pologne | Sigismund II Augustus |
| Sigismond II Rákóczi | Sigismund Rákóczi |
| Sigismond III de Pologne | Sigismund III Vasa |
| Sigismond Malatesta | Sigismondo Malatesta |
| Sigismund Thalberg | Sigismond Thalberg |
| Sigiswald Kuijken | Sigiswald Kuijken |
| Sigles de trois lettres | Three letter acronym |
| Siglistorf | Siglistorf |
| Siglufjörður | Siglufjörður |
| Sigma | Sigma |
| Sigma Corporation | Sigma Corporation |
| Sigma Librae | Sigma Librae |
| Sigma Octantis | Sigma Octantis |
| Sigma Olomouc | SK Sigma Olomouc |
| Sigma Sagittarii | Sigma Sagittarii |
| Sigma Scorpii | Sigma Scorpii |
| Sigmar Polke | Sigmar Polke |
| Sigmaringen | Sigmaringen |
| Sigmaringendorf | Sigmaringendorf |
| Sigmodontinae | New World rats and mice |
| Sigmund Freud | Sigmund Freud |
| Sigmund Jähn | Sigmund Jähn |
| Sign of the Hammer | Sign of the Hammer |
| Signac | Signac |
| signal | signal |
