| synécologie | synecology |
| Synésios de Cyrène | Synesius |
| synœcisme | synoecism |
| Syphax | Syphax |
| syphilis | syphilis |
| syphilitique | syphilitic |
| Syr-Daria | Syr Darya |
| Syracuse | Syracuse |
| Syracuse Chiefs | Syracuse Chiefs |
| Syracuse University Orange | Syracuse Orange |
| Syre | Syre |
| Syreeta Wright | Syreeta Wright |
| Syriana | Syriana |
| Syrie | Syria |
| Syrien | Syrian |
| Syrienne | Syrian |
| Syringa vulgaris | Syringa vulgaris |
| Syrmie | Syrmia |
| Syros | Syros |
| Syrphe ceinturé | Flower-fly |
| Syrrhapte | Syrrhaptes |
| Syrrhapte du Tibet | Tibetan Sandgrouse |
| Syrte | Surt |
| Syrtos | Syrtos |
| Syslinux | SYSLINUX |
| Syslog | Syslog |
| sysop | sysop |
| Syssert | Sysert |
| Syssitie | Syssitia |
| System of a Down | System of a Down |
| System on Chip | System-on-a-chip |
| Systema | Systema |
| Systema Naturae | Systema Naturae |
| Systeme a comptage de photons | Photon counting systems |
| Systeme binaire | Binary systems |
| Systeme catadioptrique | Catadioptric systems |
| Systeme catoptrique | Catoptric systems |
| Systeme de coordonnees | Coordinate systems |
| Systeme de coordonnees altazi | Horizon coordinate system |
| Systeme de coordonnees eclipt | Ecliptic coordinate system |
| Systeme de coordonnees equato | Equatorial coordinate system |
| Systeme de coordonnees galact | Galactic coordinate system |
| Systeme de coordonnees inerti | Inertial coordinate system |
| Systeme de gestion de vol | Flight management system |
| Systeme de guidage | Guide systems |
| Systeme de Johnson Morgan | Johnson Morgan system |
| Systeme de reference | Reference frames |
| Systeme de reference du catal | FK catalog system |
| Systeme de reference inertiel | Inertial frame of reference |
| Systeme de soutien | Support systems |
| Systeme de telecommande | Remote control systems |
| Systeme dioptrique | Dioptric systems |
| Systeme en ligne | On line systems |
| Systeme endocrinien | Endocrine system |
| Systeme equatorial | Equatorial system |
| Systeme fondamental | Fundamental system |
| Systeme HD | HD system |
| Systeme Henry Draper | Henry Draper system |
| Systeme optique | Optical systems |
| Systeme photometrique | Photometric systems |
| Systeme planetaire | Planetary systems |
| Systeme solaire | Solar System |
| Systeme terre lune | Earth moon system |
| Systeme UVBY | UVBY system |
| SystemRescueCd | SystemRescueCD |
| Systems Modeling Language | Systems Modeling Language |
| systolique | systolic |
| SYSTRAN | SYSTRAN |
| système | system |
| Système ABO | ABO blood group system |
| Système Argos | Argus |
| Système astéroïdal | Binary asteroid |
| système auditif | hearing system |
| système babillard electronique | bulletin board system |
| Système Basic RolePlaying | Basic Role-Playing |
| Système Buchholz | Buchholz system |
| système cardiovasculaire | cardiovascular system |
| Système catadioptrique | Catadioptric system |
| Système catoptrique | Catoptric system |
| Système central | Sistema Central |
| Système CGS | Centimetre gram second system of units |
| Système complexe | Complex system |
| Système Comstock-Needham | Comstock-Needham system |
| Système conjugué | Conjugated system |
| Système convectif de méso-échelle | Mesoscale convective system |
| Système cristallin | Crystal system |
| système d'adressage par domaines | Domain Name System |
| système d'aide à la décision | decision-support system |
| système d'alerte rapide | early warning system |
