CDO
- CDO Foodsphere
- Cagayan de Oro
- Canyon del Oro High School
- Cardonald railway station
- Cañada del Oro
- Central dense overcast
- Chief Dental Officer (United Kingdom)
- Chief Dental Officer (disambiguation)
- Chief data officer
- Chief design officer
- Chief digital officer
- Chief diversity officer
- Climate Data Operators
- Collaboration Data Objects
- Collateralized debt obligation
- Community dial office
- Connected Data Objects
- Conservative Democratic Organisation
- Continuous duty overnight
- Cysteine dioxygenase
- Eastern Min