Engineering Change Order 
Engineering Change Orders 
Economic Cooperation Organization 
Electronic Central Office 
engine combustion 
Edison Chouest Offshore 
Edit Change Order 
Electron Coupled Oscillator 
electronic combat officer 
Engine Certification Office 
Engineering Console Operator 
English Chamber Orchestra 
environmental compliance officer 
Early Childhood Outcomes 
Earth Communications Office 
Earth-Crossing Orbit 
ECHO BAY MINES LTD. 
echocardiogram 
Ecological 
ecological risk 
Ecology 
Economic Cooperation Organisation 
Ecorail Incorporated 
Ecorail, Inc. 
edge control only 
Electrical Control Operator 
Electron-Coupled Oscillator 
Electronic Collection Outstations 
Electronic Communications Office 
Electronic Contact Operator