| X BitMap | X BitMap |
| X Day | X-Day |
| X display manager | XDM |
| X Games | X Games |
| X Japan | X Japan |
| X PixMap | X PixMap |
| X-COM | X-COM series |
| X-country | Cross-country cycling |
| X-Man | Nate Grey |
| X-Men | X-Men |
| X-Or | Uchuu Keiji Gavan |
| X-wing | X-wing |
| Xabi Alonso | Xabi Alonso |
| Xabier Zandio Echaide | Xabier Zandio |
| XAML | Extensible Application Markup Language |
| XANA | Xana |
| Xanadu | Xanadu |
| Xanana Gusmão | Xanana Gusmão |
| Xanatos | Xanatos |
| Xandros | Xandros |
| XANES | XANES |
| Xanten | Xanten |
| Xanthe | Xanthos |
| Xanthe et Balios | Balius and Xanthus |
| Xanthine oxydase | Xanthine oxidase |
| Xanthippe | Xanthippe |
| xanthium | cocklebur |
| Xanthocyparis | Callitropsis |
| Xanthorrhoea | Xanthorrhoea |
| Xanthosoma | Xanthosoma |
| Xantippe | Xantippus |
| Xavante | Xavante |
| Xavi Hernández | Xavi |
| Xavier | Xavier |
| Xavier Sala-i-Martin | Xavier Sala-i-Martin |
| Xavier Tartakover | Savielly Tartakower |
| Xavières | Xaverian Brothers |
| Xavánte | Xavante language |
| XBill | XBill |
| XBoard | XBoard |
| Xcel Energy Center | Xcel Energy Center |
| XCF | XCF |
| XChat | XChat |
| XE | Xe |
| Xe dynastie égyptienne | Tenth dynasty of Egypt |
| Xel-Ha | Xelha |
| Xelaju MC | Club Xelajú MC |
| Xen | Xen |
| Xenarthra | Xenarthra |
| Xenia Alexandrovna de Russie | Grand Duchess Xenia Alexandrovna of Russia |
| Xenie Alexandrovna de Russie | Grand Duchess Xenia Alexandrovna of Russia |
| XENIX | Xenix |
| Xenopeltidae | Xenopeltidae |
| Xenophón Zolótas | Xenophon Zolotas |
| Xenopsylla cheopis | Rat flea |
| Xenosauridae | Xenosauridae |
| Xenu | Xenu |
| Xeraco | Xeraco |
| Xeresa | Xeresa |
| Xerez Club Deportivo | Xerez CD |
| Xero | Xero |
| Xeromys myoides | False Water Rat |
| Xerophyllum tenax | Xerophyllum tenax |
| Xerox | Xerox |
| Xerox Alto | Xerox Alto |
| Xerox PARC | PARC |
| Xert | Xert |
| Xerta | Xerta |
| Xerus | African ground squirrel |
| Xerxès | Xerxes |
| Xerxès Ier | Xerxes I of Persia |
| Xerxès II | Xerxes II of Persia |
| Xfce | Xfce |
| Xgl | Xgl |
| xhosa | Xhosa |
| XHTML | XHTML |
| XHTML Friends Network | XHTML Friends Network |
| xi | xi |
| Xi Andromedae | Xi Andromedae |
| Xi Jiang | Xijiang River |
| Xiamen | Xiamen |
| Xianbei | Xianbei |
| Xianfeng | Xianfeng Emperor |
| Xiangfan | Xiangfan |
| xiangqi | xiangqi |
| Xiangtan | Xiangtan |
| Xianyang | Xianyang |
| Xiao Qiao | Two Qiaos |
| XiaoXiao | Xiao Xiao |
| Xibalba | Xibalba |
| Xibe | Xibe |
| XIe dynastie égyptienne | Eleventh dynasty of Egypt |
| Xie Jun | Xie Jun |
| Xie Xingfang | Xie Xingfang |
| XIIe dynastie égyptienne | Twelfth dynasty of Egypt |
| XIIIe dynastie égyptienne | Thirteenth dynasty of Egypt |
| Xilinhot | Xilinhot |
| Xing Huina | Huina Xing |
| Xingu | Xingu |
| Xingyi quan | Xingyiquan |
| Xingzhonghui | Revive China Society |
| Xinhua | Xinhua News Agency |
| Xining | Xining |
| Xinjiang | Xinjiang |
| Xinmin Evening News | Xinmin Evening News |
| Xinyang | Xinyang |
| Xinzhou | Xinzhou |
| Xinzo de Limia | Xinzo de Limia |
| Xiongnu | Xiongnu |
| Xipe Totec | Xipe Totec |
| Xipho | Green swordtail |
| Xiphophorus variatus | Variable platyfish |
| Xiphos | Xiphos |
| Xiuhtecuhtli | Xiuhtecuhtli |
| XIVe dynastie égyptienne | Fourteenth dynasty of Egypt |
| Xiwangmu | Queen Mother of the West |
| XIXe dynastie égyptienne | Nineteenth dynasty of Egypt |
| Xizang | Tibet Autonomous Region |
| XL | XL |
| XLR | XLR connector |
| XML Key Management Specification | XKMS |
| XML Metadata Interchange | XML Metadata Interchange |
| XML Process Definition Language | XPDL |
| XML Query | XQuery |
| XML Schema | XML Schema |
| XML-based User interface Language | XUL |
| XMLHttpRequest | XMLHttpRequest |
| XMLTV | XMLTV |
| XMM-Newton | XMM-Newton |
| XMMS | XMMS |
| Xmodem | XMODEM |
| Xmoto | X-Moto |
| xoanon | xoanon |
| Xochimilco | Xochimilco |
| Xochipilli | Xochipilli |
| Xochiquetzal | Xochiquetzal |
| Xonrupt-Longemer | Xonrupt-Longemer |
| Xoops | XOOPS |
| Xouthos | Xuthus |
| Xoïs | Xois |
| XPCOM | XPCOM |
| XPInstall | XPInstall |
| XRI | Extensible Resource Identifier |
| XScale | XScale |
| Xserve | Xserve |
| XSL-FO | XSL Formatting Objects |
| Xsp | XSP |
| XSPF | XML Shareable Playlist Format |
| Xu Chu | Xu Chu |
| Xu Yuhua | Xu Yuhua |
| Xuankongsi | Hanging Temple |
| Xuanzang | Xuanzang |
| Xun Zi | Xun Zi |
| Xuxa Meneghel | Xuxa |
| Xuzhou | Xuzhou |
| XVe corps SS de cavalerie cosaque | XVth SS Cossack Cavalry Corps |
| XVe dynastie égyptienne | Fifteenth dynasty of Egypt |
| Xvid | Xvid |
| XVIe dynastie égyptienne | Sixteenth dynasty of Egypt |
| XVIIe dynastie égyptienne | Seventeenth dynasty of Egypt |
| XVIIIe corps aéroporté américain | XVIII Airborne Corps |
| XVIIIe dynastie égyptienne | Eighteenth dynasty of Egypt |
| XXe dynastie égyptienne | Twentieth dynasty of Egypt |
| XXIe dynastie égyptienne | Twenty-first dynasty of Egypt |
| XXIIe dynastie égyptienne | Twenty-second dynasty of Egypt |
| XXIIIe dynastie égyptienne | Twenty-third dynasty of Egypt |
| XXIVe dynastie égyptienne | Twenty-fourth dynasty of Egypt |
| XXIXe dynastie égyptienne | Twenty-ninth dynasty of Egypt |
| XXVe dynastie égyptienne | Twenty-fifth dynasty of Egypt |
| XXVIe dynastie égyptienne | Twenty-sixth dynasty of Egypt |
| XXVIIe dynastie égyptienne | Achaemenid dynasty |
| XXVIIIe dynastie égyptienne | Twenty-eighth dynasty of Egypt |
| XXXe dynastie égyptienne | Thirtieth dynasty of Egypt |
| XXXHOLiC | XxxHolic |
| Xylem Tube | Xylem Tube EP |
| Xylocopinae | Xylocopinae |
| xylographie | xylography |
| Xylokastro | Xylokastro |
| xylologie | xylology |
| xylophage | xylophagous |
| xylophone | xylophone |
| xylophoniste | xylophonist |
| xylose | xylose |
| xylène | xylene |
| Xàtiva | Xàtiva |
| xénarthre | xenarthran |
| Xénarthres | Xenarthra |
| Xénique de Stephen | Stephens Island Wren |
| Xénique des buissons | Bush Wren |
| xénobiologie | xenobiology |
| xénocide | xenocide |
| Xénocrate | Xenocrates |
| xénogreffe | xenotransplantation |
| xénolithe | xenolith |
| Xénomorphe | Xenomorph |
| xénon | xenon |
| Xénope | Xenopus |
| Xénophane | Xenophanes |
| Xénophane de Colophon | Xenophanes |
