| Xabi Alonso | Xabi Alonso |
| Xabi Prieto | Xabier Prieto |
| Xabier Zandio | Xabier Zandio |
| Xai Xai | Xai-Xai |
| Xai-Xai | Xai-Xai |
| Xainsomboun | Xaisomboun |
| XAML | Extensible Application Markup Language |
| XANA | Xana |
| Xanadú | Xanadu |
| Xanana Gusmão | Xanana Gusmão |
| Xander Harris | Xander Harris |
| Xandrianismo | Alexandrian Wicca |
| Xandros | Xandros |
| Xanthosoma | Xanthosoma |
| Xanti | Xanthi |
| xantina | xanthine |
| Xavantes | Xavante |
| Xavi Hernández | Xavi |
| Xavier Bichat | Marie François Xavier Bichat |
| Xavier Sala i Martín | Xavier Sala-i-Martin |
| Xbox Live Vision | Xbox Live Vision |
| XD-Picture Card | XD-Picture Card |
| XDCC | XDCC |
| XDMCP | XDM |
| XDR | External Data Representation |
| Xel-Há | Xelha |
| Xena | Xena |
| Xenarthra | Xenarthra |
| Xenicus lyalli | Stephens Island Wren |
| xenofobia | xenophobia |
| Xenofon Zolotas | Xenophon Zolotas |
| Xenoforme | Xenomorph |
| Xenophyophorea | Xenophyophore |
| Xenopus | Xenopus |
| Xenopus laevis | African clawed frog |
| Xenotarsosaurus | Xenotarsosaurus |
| xenotrasplante | xenotransplantation |
| Xenoturbellida | Xenoturbella |
| Xenu | Xenu |
| Xenócrates | Xenocrates |
| Xenófanes | Xenophanes |
| xenófoba | xenophobe |
| xenófobo | xenophobic |
| xenón | xenon |
| Xerces | Xerces |
| Xerez Club Deportivo | Xerez CD |
| Xeriscape | Xeriscaping |
| Xero | Xero |
| XeroBank Browser | XeroBank Browser |
| xeroftalmia | xerophthalmia |
| xerografía | xerography |
| Xerophyllum tenax | Xerophyllum tenax |
| Xerox | Xerox |
| Xerox Alto | Xerox Alto |
| Xerox PARC | PARC |
| Xerxes | Xerxes |
| Xestobium rufovillosum | Death watch beetle |
| XETRA | Xetra |
| Xfce | Xfce |
| XFL | XFL |
| XGA | XGA |
| Xgl | Xgl |
| xhosa | Xhosa |
| XHTML | XHTML |
| xi | xi |
| Xi Jiang | Xijiang River |
| XI Región de Aisén del General Carlos Ibáñez del Campo | Aysén Region |
| Xi Scorpii | Xi Scorpii |
| Xi Shun | Bao Xishun |
| Xi Wangmu | Queen Mother of the West |
| Xiamen | Xiamen |
| Xianbei | Xianbei |
| Xiang | Xiang River |
| Xiang Yu | Xiang Yu |
| Xibalbá | Xibalba |
| Xibe | Xibe |
| Xie Xingfang | Xie Xingfang |
| Xifos | Xiphos |
| XII Región de Magallanes y de la Antártica Chilena | Magallanes y Antártica Chilena Region |
| XIII Concilio de Toledo | Thirteenth Council of Toledo |
| xilano | xylan |
| xilema | xylem |
| xileno | xylene |
| xilitol | xylitol |
| xilofonista | xylophonist |
| Xilofón | Xylophone |
| xilografía | xylography |
| xilosa | xylose |
| xilulosa | xylulose |
| xilófono | xylophone |
| Xilógrafo | Wood engraver |
