| 序号 | 英文 | 音标 | 词性 | 中文 |
| | OGTC | | | =outgoing toll[trunk] center 去话长途电话中心局 |
| | OHMS | | abbr. | On His Majesty's Service 英国政府信件不用邮资印 |
| | OHP | | abbr. | [军] Overhead Protection, 顶置防护 |
| | OHS open hearth steel | | | 平炉钢 |
| | OICQ | | | 一个常用的网上聊天工具，由腾讯公司研制。 |
| | OIRT | | | =Organisation Internationale de Radiodiffusion et Television (=Internation Radio and Television Organization)园际广播电视组织[法] |
| | OIT | | abbr. | Office of International Trade(美国)国际贸易局 |
| | OIWC | | | =Oil-Insulated Water-Cooled Img 油绝缘水冷式(变压器) |
| | OJ | `EudVeI | abbr. | Orange Juice,橘汁,橙汁 |
| | OJT | | abbr. | On the Job Training ,在职训练 |
| | OK | | adj. | 1.很好的 2.还不错的 |
| | OK lamp | | | 绿灯(表示"准备完毕"的绿色信号灯) |
| | OKI | | n. | 冲电气(日本著名的电子公司) |
| | OKLA. | | | Oklahoma 美国俄克拉荷马州州名 |
| | OLB | | | 带有类型库资源的一种特殊的动态链接库，也叫对象库文件。 |
| | OLC | | | =On Line Code 线内编码 |
| | OLE | | n. | 对象链接和嵌入 |
| | OLTEP | | | =On-Line Test Executive Program 联机测试执行程序 |
| | OLTP | | abbr. | 联机事务处理 |
| | OM | | abbr. | （英国）功绩勋章（获得者） |
| | OMA | `EumE | abbr. | orderly marketing agreement有秩序的市场销售协定 |
| | OMG | | abbr. | [军] Overhead Mounted Gun, 顶置炮 |
| | OMR | | abbr. | [计]光标阅读器 |
| | OMRE | | | =Organic Moderated Reactor Experiment 有机慢化剂反应堆试验 |
| | OMS | | | =Organic Mass Spectrometry 《有机质谱测定法》(期刊)[英] |
| | OMT | | | =Orth-Mode Transducer[无]直接式收发转换器 |
| | ONC | | abbr. | （英国煤矿技术人员）国家普通合格证书 |
| | OND | | abbr. | （英国）国家正式毕业证书 |
| | ONI | | abbr. | Office of Naval Intelligence (美国)海军情报局 |
| | ONO | | abbr. | Or the Neareat Offer 或最近报价 |
| | ONR | | abbr. | Office of Naval Research(美国)海军研究局 |
| | ONT. | | | Ontario 加拿大安大略省省名 |
| | OO | `Eu`Eu | | (=Object Oriented)面向对象的 |
| | OOA | | abbr. | 面向对象分析 |
| | OOAA | | | =Olive Oil Association of America 美国橄榄油协会 |
| | OOB | | | =off-off-Broadway 纽约第三戏剧界 |
| | OOD | | abbr. | 面向对象设计 |
| | OODB | | abbr. | 面向对象数据库 |
| | OODBS | | abbr. | 面向对象数据库系统 |
| | OODM | | abbr. | 面向对象数据模型 |
| | OOL | | | =Operator-Oriented Language 面向操作员的语言 |
| | OOP | | abbr. | Object Oriented Programming, 面向对象的程序设计 |
| | OOPM | | abbr. | 面向对象程序设计方法学 |
| | OOPS | | | =ON-line Object-Patching System联机物体临时接线系统 |
| | OOS | | abbr. | Out Of Stock 缺货, 无库存 (=OS) |
| | OP | 5Eup | abbr.；abbr. | abbr. [军] Observation Post, 观察所；abbr. [军] Opposed, 对置发动机；abbr. 操作员(=Operater) |
| | OPA | | | =Office of Price Administration物价管理局[美] |
| | OPDAR | | | =Optical Direction And Ranging 光学定向和测距, 光雷达 |
| | OPEC | 5Eupek | n. | 石油输出国家组织 |
| | OPFOR | | abbr. | [军] Opposing Forces, 敌对双方部队 |
| | OPL | | | =Official Publications Library官方出版物图书馆[英] |
| | OPLE | | | =Omega Positioning and Locating Equipment 奥米伽定位设备 |
| | OPLR | | | =Outpost Line of Resistance 警戒防御线 |
| | OPM | | | =Office of Procurement and Material 采购器材局[美军] |
| | OPS | Cps | abbr. | Office Price Stabilization,物价管制局 |
| | OPS. | | | operations 手术 |
| | OPT | | | VC开发环境自动生成的用来存放WorkSpace中各种选项的文件。 |
| | OPTAA | | | =Optical Automatic Ranging 光学自动测距仪 |
| | OPTAR | | abbr. | [军] Optical Tracking Acquisition and Ranging, 光学跟踪、搜索与测距 |
| | OPTRAC | | abbr. | [军] Optical Tracking-light Beam Rangefinder System, 光学跟踪-光学测距仪系统 |
| | OR | | | =Operating Room 手术室 |
| | OR circuit | | | [计]"或"电路 |
| | OR function | | | [自]"或"功能 |
| | OR output | | | “或”输出 |
| | OR tree | | | “与/或”树 |
| | ORACLE | | | =Oak Ridge Automatic Computer and Logical Engine 橡树岭自动计算机和逻辑机([美]橡树岭实验室) |
| | ORB | | | =Oceanographic Research Buoy海洋学研究浮标 |
| | ORC | | | =Operations Research Center 运筹学中心 ([美] California大学) |
| | ORD | | | =Office for Research and Development研究与开发处 |
| | ORDIR | | | =Omnidirectional Digital Radar 全向数字式雷达 |
| | ORINS | | abbr. | Oak Ridge Institute of Nuclear Studies(美国) 橡树岭原子核研究所 |
| | ORNL | | abbr. | Oak Ridge National Laboratory (美国)国立橡树岭实验所 |
| | ORP | | | =Orbital Rendezvous Procedure 轨道会合程序 |
| | OS | | abbr. | Operating System n.操作系统 |
| | OSA | | abbr. | Order of St. Augustine (天主教)奥斯定会 |
| | OSB | | abbr. | Order of St. Benedict (天主教)本笃会 |
| | OSD | | | =Ocean Sciences Division 海洋科学部([美]NRL) |
| | OSEE | | | =Optically Stimulated Exoelectron Emission 光激发外逸电子发射 |
| | OSEM | | | =Office of Systems Engineering and Management 系统工程和管理处([美]FAA) |
| | OSF | | abbr. | Order of St. Francis (天主教)方济各会 |
| | OSFCW | | abbr. | Office of Solid Fuels Coordinator for War ( 第二次世界大战时的)作战用固体燃料协调人办事处 |
| | OSFILE | | abbr. | [计]操作系统文件 |
| | OSHA | | | =Occupational Safety and Health Act [Adiministration] 职业安全与卫生条例[管理局][美] |
| | OSI | | abbr. | Open System Interconnect Reference Model, 开放式系统互联参考模型 |
| | OSIE | | abbr. | [计]开放系统互连环境 |
| | OSIRM | | abbr. | [计]开放系统互连模式 |
| | OSO | | | = Orbital Solar Observatory 轨道太阳观测卫星 |
| | OSP | | abbr. | Optical Signal Processor ,光信号处理器 |
| | OSR | | | =Office of Scientific Research 科学研究局([美]USAF) |
| | OSRD | | abbr. | Office for Scientific Research and Development (美国)科学研究与发展局 |
| | OSS | | | =Office of Space Sciences 航天科学局[美] |
| | OSSA | | | =Office of Space Science and Applications 航天科学与应用处([美]NASA) |
| | OST | | abbr. | Office of Science and Technology (美国)科学技术局 |
| | OSTAC | | | =Ocean Science and Technology Advisory Committee 海洋科学技术咨询委员会 |
| | OSTD | | | =Office of Supersonic Transport Development 超音速运输机开发处([美]USDT) |
| | OSW | | | =Office of Saline Water 咸[海]水淡化处([美]USDI) |
| | OT | | abbr.；abbr. | abbr. [军] Operational Test, 适用性试验；abbr. Old Testament ,<<圣经旧约>>；abbr. (=overtime) 加班 |
| | OTA | | abbr. | [军] Overflying-Top Attack, 飞越顶部攻击 |
| | OTB | | abbr. | offtrack betting 场外赛马赌博 |
| | OTC | | | =Office of Technical Cooperation技术合作处(联合国) |
| | OTEC | `Eutek | n. | 海洋热能转换系统 |