| X and Y bosons | Bosón X |
| X Article | Las fuentes del comportamiento soviético |
| X Factor | Factor-X |
| X Games | X Games |
| X Japan | X Japan |
| X ray | Rayos X |
| X ray absorption | Absorción de los rayos X |
| X ray astronomy | Astronomía X |
| X ray background | Fondo de radiación X |
| X ray binary star | Estrella doble de rayos X |
| X ray bright point | Mancha de rayos X |
| X ray burst | Destello X |
| X ray continuum | Espectro contínuo UV |
| X ray detector | Detector de rayos X |
| X ray diffraction | Difracción de rayos X |
| X ray emission | Emisión de rayos X |
| X ray fluorescence | Fluorescencia X |
| X ray identification | Identificación de fuente X |
| X ray line | Línea X |
| X ray luminosity | Luminosidad en rayos X |
| X ray nova | Nova X |
| X ray observatory | Observatorio de rayos X |
| X ray polarization | Polarización de rayos X |
| X ray pulsar | Pulsar X |
| X ray quasar | Cuasar X |
| X ray radiation | Radiación X |
| X ray scattering | Dispersión de los rayos X |
| X ray source | Fuente X |
| X ray spectroscopy | Espectrocopía en rayos X |
| X ray spectrum | Espectro de rayos X |
| X ray star | Estrella X |
| X ray structure | Estructura de rayos X |
| X ray telescope | Telescopio de rayos X |
| X ray transients | Objeto X temporal |
| X rays | Rayos X |
| X window manager | Gestor de ventanas |
| X-chromosome | cromosoma X |
| X-COM series | X-COM |
| X-convention | Convención x |
| X-Factor | Factor-X |
| X-mas | Navidad |
| X-Men | X-Men |
| X-radiation | Rayos X |
| X-ray | radiografiar |
| X-ray crystallography | cristalografía de rayos X |
| X-ray photo | Radio |
| X-ray photography | Radio |
| X-ray picture | radiografía |
| X-rays | rayos X |
| X-wing | X-Wing |
| Xabi Alonso | Xabi Alonso |
| Xabier Prieto | Xabi Prieto |
| Xabier Zandio | Xabier Zandio |
| Xacuti | Chacuti |
| Xagħra | Caza |
| Xai-Xai | Xai Xai |
| Xaisomboun | Xainsomboun |
| Xalapa | Xalapa |
| Xallas | Comarca del Xallas |
| Xana | XANA |
| Xanadu | Xanadú |
| Xanadu House | Xanadú |
| Xanana Gusmão | Xanana Gusmão |
| Xander Harris | Xander Harris |
| Xandros | Xandros |
| Xanthi | Xanti |
| Xanthi Prefecture | Xanti |
| xanthine | xantina |
| Xanthippe | Xanthippa |
| Xanthippus of Carthage | Jantipo |
| Xanthophyceae | Chrysophyta |
| Xanthos | Janto |
| Xanthosoma | Xanthosoma |
| xanthous | ocre |
| Xarel·lo | Uva xarel·lo |
| Xavante | Xavantes |
| Xavante language | Idioma xavante |
| Xaver | Javier |
| Xavi | Xavi Hernández |
| Xavier | Javier |
| Xavier Sala-i-Martin | Xavier Sala i Martín |
| Xbox Live Marketplace | Bazar Xbox Live |
| Xbox Live Vision | Xbox Live Vision |
| XChat | X-Chat |
| XD-Picture Card | XD-Picture Card |
| XDCC | XDCC |
| XDM | XDMCP |
| XDR DRAM | XDR |
| Xe | Xenón |
| xebec | jabeque |
| Xedos | Mazda Xedos |
| Xelha | Xel-Há |
| Xena | Xena |
| Xenarthra | Xenarthra |
| Xenix | Microsoft XENIX |
| Xenocrates | Jenócrates |
