| Acronym | Definition |
|---|
| ACSI➣Association of Christian Schools International |
| ACSI➣American Customer Satisfaction Index |
| ACSI➣Association Canadienne des Sciences de l'Information (French) |
| ACSI➣Army Chief of Staff for Intelligence (US DoD) |
| ACSI➣American Communications Services, Inc. (telecommunications company) |
| ACSI➣Anglo-Chinese School (Independent) |
| ACSI➣Atari Computer System Interface |
| ACSI➣Appalachian Clean Streams Initiative |
| ACSI➣Association of Clinical Scientists in Immunology (United Kingdom) |
| ACSI➣Alcoa Closure Systems International (various locations) |
| ACSI➣Antiguo Colegio de San Ildefonso (museum in Mexico City) |
| ACSI➣Afghanistan Civil Service Institute |
| ACSI➣Advanced Computer System Interface |
| ACSI➣America's Counter-Smuggling Initiative |
| ACSI➣Abstract Communications Service Interface |
| ACSI➣Airport Certification Safety Inspector (FAA) |
| ACSI➣Alcan Composites, Singen (European aluminum plant) |