| X band | Bande X |
| X BitMap | X BitMap |
| X class submarine | Classe X |
| X display manager | X display manager |
| X Factor | Facteur-X |
| X Games | X Games |
| X Japan | X Japan |
| X PixMap | X PixMap |
| X ray absorption | Absorption des rayons X |
| X ray astronomy | Astronomie X |
| X ray background | Fond de rayonnement X |
| X ray binary stars | Etoile double a rayonnement X |
| X ray bright points | Spot de rayonnement X |
| X ray bursts | Sursaut X |
| X ray continuum | Spectre continu de rayonnemen |
| X ray detectors | Detecteur de rayonnement X |
| X ray diffraction | Diffraction du rayonnement X |
| X ray emission | Emission de rayonnement X |
| X ray flares | Eruption X |
| X ray fluorescence | Fluorescence X |
| X ray identifications | Identification de source X |
| X ray lines | Raie X |
| X ray luminosity | Luminosite en rayonnement X |
| X ray maps | Cartographie en rayonnement X |
| X ray novas | Nova X |
| X ray observatories | Observatoire pour le rayonnem |
| X ray polarization | Polarisation du rayonnement X |
| X ray pulsars | Pulsar X |
| X ray quasars | Quasar X |
| X ray radiation | Rayonnement X |
| X ray scattering | Diffusion des rayons X |
| X ray sources | Source X |
| X ray spectra | Spectre de rayonnement X |
| X ray spectrographs | Spectrographe a rayons X |
| X ray spectrometers | Spectrometre a rayons X |
| X ray spectroscopy | Spectroscopie en rayons X |
| X ray stars | Etoile X |
| X ray structure | Structure en rayonnement X |
| X ray surveys | Releve en rayons X |
| X ray telescopes | Telescope pour rayons X |
| X ray transients | Objet X temporaire |
| X rays | Rayon X |
| X unit | Siegbahn |
| X window manager | Gestionnaire de fenêtres |
| x-axis | axe des x |
| X-bar theory | Théorie X-barre |
| X-chromosome | chromosome X |
| X-COM series | X-COM |
| X-Day | X Day |
| X-Factor | Facteur-X |
| X-linked agammaglobulinemia | Agammaglobulinémie liée au sexe |
| X-mas | Noël |
| X-Men | Les X-Men |
| X-Moto | Xmoto |
| X-radiation | Rayon X |
| X-ray | radiographier |
| X-ray binary | Binaire X |
| X-ray crystallography | Diffractométrie de rayons X |
| X-ray diffraction | Diffractométrie de rayons X |
| X-ray fluorescence | Spectrométrie de fluorescence X |
| X-ray photoelectron spectroscopy | Spectrométrie photoélectronique X |
| X-ray picture | radio |
| X-ray spectroscopy | Spectrométrie de fluorescence X |
| X-rays | rayons X |
| X-wing | X-wing |
| Xabi Alonso | Xabi Alonso |
| Xabier Zandio | Xabier Zandio Echaide |
| Xagħra | Chasse |
| Xai-Xai | Xai-Xai |
| Xaignabouli | Province de Sayaboury |
| Xaignabouli Province | Province de Sayaboury |
| Xainza County | Comté de Xainza |
| Xaisomboun | Zone spéciale de Xaysomboun |
| Xalapa | Jalapa |
| Xana | XANA |
| Xanadu | Xanadu |
| Xanadu House | Maison Xanadu |
| Xanana Gusmão | Xanana Gusmão |
| Xanatos | Xanatos |
| Xander Harris | Alexander Harris |
| Xandros | Xandros |
| XANES | XANES |
| Xanten | Xanten |
| Xanten Cathedral | Cathédrale Saint-Victor de Xanten |
| Xanth | Xanthe |
| Xanthine oxidase | Xanthine oxydase |
| Xanthippe | Xanthippe |
| Xanthippus of Carthage | Xanthippe |
| Xanthophyceae | Chrysophyceae |
| Xanthorrhoea | Xanthorrhoea |
| Xanthos | Xanthe |
| Xanthosoma | Xanthosoma |
| xanthous | ocre |
| Xantusiidae | Xantusiidae |
| Xavante | Xavante |
| Xavante language | Xavánte |
| Xaver | Javier |
| Xaverian Brothers | Xavières |
| Xavi | Xavi Hernández |
| Xavier | Xavier |
| Xavier Sala-i-Martin | Xavier Sala-i-Martin |
| XBill | XBill |
| XBoard | XBoard |
