| Syn and Anti addition | Syn |
| SYN cookies | SYN cookie |
| SYN flood | SYN flood |
| synaesthesia | synesthésie |
| synagogue | synagogue |
| Synagogue of El Transito | Synagogue El Transito de Tolède |
| synalepha | synalèphe |
| Synapomorphy | Synapomorphie |
| synapse | synapse |
| Synapsida | Mammifère |
| Synaptic Package Manager | Synaptic |
| Synaptic plasticity | Plasticité synaptique |
| Synaptic vesicle | Vésicule synaptique |
| Synarchism | Synarchie |
| Synaspismos | Synaspismós |
| Synbranchiformes | Synbranchiformes |
| synchrocyclotron | synchrocyclotron |
| synchromesh | synchronisation |
| synchronic | synchronique |
| synchronised skating | patinage synchronisé |
| synchronised swimming | nage synchronisée |
| synchronization | synchronisation |
| synchronize | synchroniser |
| synchronized diving | plongeon synchronisé |
| Synchronized Multimedia Integration Language | Synchronized Multimedia Integration Language |
| synchronized skating | patinage synchronisé |
| synchronized swimming | natation synchronisée |
| Synchronized swimming at the Summer Olympics | Natation synchronisée aux jeux Olympiques |
| synchronous | synchrone |
| Synchronous detectors | Detecteur synchrone |
| Synchronous optical networking | SONET |
| Synchronous rotation | Rotation synchrone |
| synchrotron | synchrotron |
| Synchrotron light | Rayonnement synchrotron |
| Synchrotron radiation | Rayonnement synchrotron |
| synclinal | synclinal |
| syncopate | syncoper |
| syncope | syncope |
| syncretic | syncrétique |
| syndical | syndical |
| syndicalism | syndicalisme |
| syndicalist | syndicaliste |
| syndicate | syndicat |
| syndrome | syndrome |
| synecdoche | synecdoque |
| synecology | synécologie |
| synergy | synergie |
| Synesius | Synésios de Cyrène |
| Synesthesia | Synesthésie |
| Syngman Rhee | Syngman Rhee |
| Syngnathidae | Syngnathidae |
| Syngnathiformes | Syngnathoidei |
| synod | synode |
