X-rays 4,248 Xenophobia 1,626 X-ray spectroscopy 902 X-ray astronomy 854 XML (Document markup language) 750 X-Men (Fictitious characters) 658 X-ray crystallography 614 Xhosa (African people) 468 X-Rays 465 Xhosa language 459 X-ray optics 384 Xenobiotics 279 Xiao xue lei 267 Xiongnu (Asian people) 243 Xi Xia Dynasty (China) 219 Xiao shuo ji 215 Xiang sheng 211 X-ray lithography 208 X-ray sources, Galactic 203 XML (Langage de balisage) 198 X Window System (Computer system) 192 XML 192 X-ray lasers 184 Xenon 167 Xavante Indians 140 XHTML (Document markup language) 126 X rays 120 X-Ray Therapy 118 Xylophone music 115 X-Ray Diffraction 113 Xénophobie 110 Xiang dialects 110 Xiao shuo lei 109 Xenopus laevis 106 Xenografts 95 Xiao xiao shuo 93 Xhosa poetry 92 X ray astronomy 91 Xhosa fiction 90 X-ray telescopes 88 X-ray binaries 86 X-ray microanalysis 81 X-15 (Rocket aircraft) 78 Xeriscaping 71 X-ray microscopes 69 X ray sources 68 Xylem 67 Xerophytes 66 X ray spectra 65 X-ray diffraction 65 Xanth (Imaginary place) 63 Xylene 63 X-ray microscopy 59 Xenarthra 59 Xylophone 58 Xerography 57 Xhosa 57 Xianbei (Asian people) 55 Xuan ji 55 Xing style 53 Xml (Document Markup Language) 53 Xiao shuo jia lei 51 Xenopus 49 Xylophone with orchestra 48 Xenomorphs (Fictitious characters) 47 Xiao shuo yan jiu 47 Xue shu si xiang 47 XHTML (Langage de balisage) 46 Xhosa literature 46 X-ray diffractometer 45 Xing fa 45 XSLT (Computer program language) 44 XXe siècle 43 Xiao shuo 43 X-ray absorption near edge structure 42 Xin shi 42 X-ray photoelectron spectroscopy 41 XXème siècle 41 Xian dai shi 39 Xiao shi 36 Xénophobie 36 Xhosa drama 35 Xerophthalmia 34 X-ray bursts 33 Xenarthra, Fossil 33 Xikrin Indians 32 XIXe siècle 31 Xi Wang Mu (Taoist deity) 31 Xiao music 31 Xun gu 31 X chromosome 30 Xbox video games 30 Xian dai wen xue 30 X ray diffraction 29 XYZ Affair, 1797-1798 29 Xangô (Cult) 29 Xavante language 29 Xiang zhai xiang mu 29 Xylitol 27 X-33 reusable launch vehicle 26