| ACOS | Associazione Cattolica Operatori Sanitari (Italian: Catholic Association of Medics and Paramedics) | Cattolica Operatori Sanitari协会（意大利语：天主教医务人员协会） |
| ACOS | American College of Osteopathic Surgeons | 美国骨科外科医生学会 |
| ACOS | Anti-Capitalist Operating System | 反资本主义操作系统 |
| ACOS | Advisory Committee on Safety (IEC) | 安全咨询委员会（IEC） |
| ACOS | Australian Chamber Of Shipping | 澳大利亚航运商会 |
| ACOS | At Change of Shift | 换班时 |
| ACOS | Assistant Chief Of Staff | 助理参谋长 |
| ACOS | ACCS Common Operating System | ACCS通用操作系统 |
| ACOS | Automated Commissary Operations System | 自动化政委操作系统 |
| ACOS | Adjustable Coil Over Spacer | 垫片上的可调线圈 |
| ACOS | Automatic Change-Over Switch | 自动转换开关 |
| ACOS | Australian Centre for Olympic Studies | 澳大利亚奥林匹克研究中心 |
| ACOS | Army Common Operating System | 陆军通用操作系统 |
| ACOS | Aircraft Certification Office Subsystem | 飞机认证办公室子系统 |
| ACOS | Adaptive Cognitive Orthosis Shell | 自适应认知矫形器外壳 |
| ACOS | Associate Chief of Staff | 副参谋长 |
| ACOS | A Change of Seasons (Dream Theater album) | 季节的变化（梦剧场专辑） |
| ACOS | A Crown of Swords (Wheel of Time; book 7) | 剑之冠（时间之轮；第7册） |
| ACOS | Arc Cosine (Inverse Cosine) | 弧余弦（反余弦） |
| ACOS | Assistant Chiefs Of Staff | 参谋长助理 |