| 序号 | 英文 | 音标 | 词性 | 中文 |
| | Wusuli | `wU:9sU:`li: | | River 乌苏里江[黑龙江支流] |
| | Wuxi | `wU:`Fi: | | 无锡[江苏省](旧译Wusih 或 Wuhsi) |
| | Wyandot | 5waiEndCt | | 怀安多特语(休伦语中一种方言) |
| | Wyandotte | 5waiEndCt | | 怀恩多特鸡(美国卵肉兼用品种鸡) |
| | Wyatt | `waIEt | n. | 怀亚特(亦作Wyat)(m.) |
| | Wykehamist | 5wikEmist | adj. | （英国公立学校） |
| | Wyo. | | | Wyoming 美国怀俄明州州名 |
| | Wyoming | wai5EumiN | n. | 怀俄明州(美国州名) |
| | Wyomingite | | n. | 怀俄明州人 |
| | Wystan | `wIstLn | n. | 威斯坦(m.) |
| | X | | | X级电影，成人电影（十八岁以下儿童不得观看） |
| | X Wt | | | =Experimental Weight 实验重量 |
| | X axis X | | | 轴, 横座标轴 |
| | X chromosome | 5ekskrEumEsEum | n. | [生]X染色体(性染色体的一种) |
| | X factor | | n. | 未知因素 |
| | X particle | | n. | [核]X粒子, 介子 |
| | X punch X | | | 穿孔, 负数穿孔 |
| | X ray | | n. | X光 |
| | X-certificate | | n. | X级(成人级) |
| | X-disease | `eksdI9zi:z | n. | [兽医]角化过度, 表皮角化病 |
| | X-film | 5eks5film | n. | 限制级电影 |
| | X-irradiate | 5eksi5reidieit | v. | 以X光照射 |
| | X-radiate | | v. | [医]以X光照射 |
| | X-rated | `eks9reItId | | (青少年禁看的)X级片 |
| | X-ray | 5eks5rei | | X-rays X光，X射线 |
| | XA | | | =Auxiliary Amplifier 辅助放大器 |
| | XAAM | | | =Experimental Air-to-Air Missile 实验型空对空导弹 |
| | XASM | | | =Experimental Air-to-Surface Missile 实验型空对地导弹 |
| | XBM | | | (X-Windows Bitmaps)黑白位图文件格式。 |
| | XBR | | | =Experimental Breeder Reactor 实验性增殖反应堆 |
| | XCA | | | =Xylenol Carboxylic Acid 二甲苯酚酸 |
| | XCIII | | num. | 罗马数字 93 |
| | XCL | | | =Excess Current Liabilities 短期债务逾额 |
| | XCR | | | =Crystal Controlled Receiver 晶体控制接收机 |
| | XCT | | | =X-band Communications Transponder X波段通信应答器 |
| | XCV | | num. | 罗马数字 95 |
| | XCVIII | | num. | 罗马数字 98 |
| | XCVR | | abbr. | [军] Transceiver Unit, 收发机装置 |
| | XD | | | ex-dividend无股息, 无红利 |
| | XDC | | | =Xylene Dichloride 二氯(代)二甲苯 |
| | XDCR | | | =Transducer 换能器, 传感器, 变频器, 转换器, 发送器 |
| | XDI | | | =Xylene Diisocyanate 二异氰酸二甲苯酯 |
| | XDP | | | =X-ray Density Probe X-射线密度探头[探测器] |
| | XDS | | | =Experimental Development Specification 实验发展规格 |
| | XDT | | | =Xenon Discharge Tube 氙放电管 |
| | XF | | abbr. | extra fine (白兰地规格, 藏窖年份75年以上) |
| | XFA | | | =Crossed-Field Acceleration 交叉场加速度 |
| | XGAM | | | =Experimental Guided Air Missile 实验性空中制导导弹 |
| | XHV | | | =Extreme Height Vacuum 极高真空 |
| | XIA | | | =X-band Interferometer Antenna X 波段[频带]干扰仪天线 |
| | XIC | | | =Tranmission Interface Converter 传输接口转换器 |
| | XII | | num. | 罗马数字 12 |
| | XIII | | num. | 罗马数字 13 |
| | XIM | | | =X-ray Intensity Meter X射线强度计 |
| | XIO | | | =Execute Input Output 执行输入输出 |
| | XIQ | | | =X-ray Industrial Quantometer 工业用X射线剂量计 |
| | XIR | | | =Extreme Infrared 超红外 |
| | XIRS | | | =Xenon Infrared Searchlight 氙红外光探照灯 |
| | XIV | | num. | 罗马数字 14 |
| | XIX | | num. | 罗马数字 19 |
| | XL | | abbr. | extra large , 特大号 |
| | XLR | | | =Experimental Liquid Rocket 实验液体燃料火箭(发动机) |
| | XLS | | | Microsoft Excel工作簿格式。 |
| | XLWB | | | =Extra-Long Wheelbase 超长轴距 |
| | XMC | | | =Xylene Monochloride 一氯代二甲苯 |
| | XMODEM | | | 一种文件传输协议 |
| | XMP | | | =xanthosine monophosphate 黄苷酸, 黄苷一磷酸 |
| | XMS memory | | n. | 扩充内存 |
| | XMS memory locked | | n. | 扩充内存锁定 |
| | XMT | | | =X-band Microwave Transmitter X 波段微波发射机 |
| | XNS | | abbr. | Xerox Network Sytem, 施乐网络系统 |
| | XO | | abbr. | extra old (白兰地规格, 藏窖年份40-75年) |
| | XOR | | | =Exclusive OR “异” 或(逻辑运算) |
| | XORM | | | =Exclusive OR Matrix 异或矩阵 |
| | XOS | | | =Extra Outsize (衣服等)特大号 |
| | XP | | | =Exercise Priority 运用优先权 |
| | XPM | | | (X-Windows Pixelmaps)彩色图象文件格式。 |
| | XPS | | | =Expanded Polystyrene 多孔聚苯乙烯 |
| | XQ | | | =Cross-Question交叉问题, 相互提问 |
| | XR | | abbr. | ex rights 无权认购新股 |
| | XRD | | | =X-ray Diffraction X射线衍射 |
| | XREP | | | =Auxiliary Report 辅助报告 |
| | XRF | | | =X-ray fluorescence X射线荧光 |
| | XRM | | | =X-Ray Microanalyser X射线微量分析仪 |
| | XROI | | | =X-Ray Optical Interferometer X射线光干涉仪 |
| | XRP | | | =X-Ray Photofluorography X射线荧光屏图象摄影 |
| | XRPM | | | =X-Ray Projection Microscope X射线投影显微镜 |
| | XRT | | | =X-Ray Technique X射线技术 |
| | XS | | | 〈服装〉特小号 |
| | XSM | | | =Experimental Strategic Missile 实验战略导弹 |
| | XSSM | | | =Experimental Surface-to-Surface Missile“地对地”实验导弹 |
| | XSTR | | | =Extra Strong 超强, 极强 |
| | XT | | | =Cross Talk 串音 |
| | XTA | | | =X-band Tracking Aerial [Antenna]X波段跟踪天线 |
| | XTLO | | | =Crystal Oscillator 晶体振荡器 |
| | XU | | | =Experimental Underwater 水下试验 |
| | XUV | | | =Extreme Ultra-Violet 超紫外线, 远紫外线(波长等于200-2000 埃) |
| | XV | | n. | 罗马数字之十五, 十五人组成的球队 |
| | XVI | | num. | 罗马数字 16 |
| | XVII | | num. | 罗马数字 17 |
| | XVIII | | num. | 罗马数字 18 |