| Encyclopedia Of Chess Openings | Chess | ECO |
| English And Cultural Orientation | University | ECO |
| Engineering Change Order | Business | ECO |
| Energy Committed To Offenders | Law | ECO |
| Electronic Collections Online | Internet | ECO |
| Earth Communications Office | NASA | ECO |
| Energy Cost Optimization | Education | ECO |
| Enterprise Core Object | Computer Software | ECO |
| Earth Crossing Objects | NASA | ECO |
| Echo Bay Mines, LTD. | AMEX Symbol | ECO |
| Ex Caelis Oblatus | Latin | ECO |
| Enterprise Customer Optimization | Business | ECO |
| ECORAIL Incorporated | Regional Railroad | ECO |
| electronic checkout | Government | ECO |
| Elected County Official | Government | ECO |
| Estudios Comerciales De Opinión | Spanish | ECO |
| Enterprise Core Objects | Computer Software | ECO |
| equipment control officer | Government | ECO |
| Epichlorohydrin Rubber (Ethylene Oxide Copolymer) | Plasctic | ECO |
| Embedded Communication Object | Computer Networking | ECO |
| Ecological | Environmental | ECO |
| Environmental Caring Organization | Clothes | ECO |
| Education for Change, Oakland | Organization | ECO |
| Economics | University | ECO |
| Earth Community Organization | Organization | ECO |
| emergency control officer | Government | ECO |
| El Encanto, Colombia | Regional Airport Code | ECO |
| electron-coupled oscillator | Government | ECO |
| Evolving Creative Opportunities | Community | ECO |
| complex relation object | Government | ECO |
| Engine Cutoff | Space Science | ECO |
| Einstein Center One | Medical | ECO |
| El Encanto | Airport Code | ECO |
| Exchange Client Object | Networking | ECO |
| Equal Credit Opportunity | Banking | ECO |
| Economic Cooperation Organization | Organization | ECO |
| ELINT collection outstation | Government | ECO |
| Engine Combustion | Space Science | ECO |
| Electronic Commerce Operator | Job Title | ECO |
| Electronic Combat Officer | Military and Defence | ECO |
| Enumerating Combinatorial Objects | Maths | ECO |
| Earthschildren Cultural Organization | Organization | ECO |
| Events, Constraints, and Objects | Maths | ECO |
