| Acronym | Definition |
|---|
| ECSO | Etowah County Sheriff's Office (Gadsden, AL) |
| ECSO | Emergency Communications of Southern Oregon (Medford, OR) |
| ECSO | Eastern Connecticut Symphony Orchestra (New London, CT) |
| ECSO | European Council of Skeptical Organizations |
| ECSO | Educational Career Services Office (University of Illinois) |
| ECSO | Environmental Civil Society Organization |
| ECSO | Économie et Coordination du Sud Ouest (French: Economy and Coordination of the Southwest) |
| ECSO | Emerald City Swing Orchestra (Dublin, OH) |
| ECSO | Enterprise Computing Solutions Organisation |
| ECSO | English and Communication Student Organization (Potsdam University; New York) |
| ECSO | Eton College Symphony Orchestra |