| Collegia Osvaldo Cruz | Academic & Science |
| Carl Orff Canada | Academic & Science |
| Cost of Capital | Accounts and Finance |
| Cash On Confirmation | Accounts and Finance |
| Certificate Of Completion | Business |
| Certificate Of Coverage | Business |
| Conditions of Contract | Business |
| Certificate Of Competency | Business |
| Centennial Outdoor Center | Business |
| Crab's Olive Cream | Business |
| Certificate of Confidentiality | Business |
| Conoco, Inc. (now ConocoPhillips, COP) | Business |
| Certified Outpatient Coding | Business |
| Certified Outpatient Coder | Business |
| Certificate Of Clearance | Business |
| Cash Or Credit | Business |
| Cross Ocean Company | Business |
| Cash On Collection | Business |
| Certification of Conformity | Certifications |
| Canadian Opera Company | Community |
| Church Of Christ | Community |
| Christian Outreach Centre | Community |
| Cultureel Ontspannings Centrum | Community |
| Council Of Clerics | Community |
| Circle Of Companions | Community |
| Corrosion Of Conformity | Community |
| Committee on Committees | Community |
| Christian Opportunity Center | Community |
| Common Ownership Communities | Community |
| Ceremony Of Carols | Community |
| Colby Outing Club | Community |
| Cascade Orienteering Club | Community |
| Confederation of Clubs | Community |
| Church Of Clancy | Computing |
| Chip On Ceramic | Computing |
| Circuit Order Control | Computing |
| Coded Optical Character | Computing |
| Channelized Optical Carrier | Computing |
| Central Office Connections | Computing |
| Convention On Cybercrime | Computing |
| Cyber Operations Center | Computing |
| Contact Order Correction | Contact |
| Coin of champions | Cryptocurrency |
| CocktailBar | Cryptocurrency |
| Commission On Colleges | Educational Institute |
| College of The Canyons | Educational Institute |
| College of Computing | Educational Institute |
| Cost of Consummables | Electronics |
| Center for Obby Creation | General |
| Chicas On Candy | General |
| Center On Cell | General |
| Crotchety Old Coot | General |
| Constituent Of Concern | General |
| A Corporations Organization For Campaigns | General |
| Cream On Cream | General |
| Cob On Carl | General |
| Container Operations Center | General |
| Challenge On Channel | General |
| Center of Competence | General |
| Call of Chernobyl | General |
| Combined Operations Center | General |
| Contractor Of Choice | General |
| Cone of Cold | General |
| Constant Overhead Charges | General |
| Change of Circumstance | General |
| Cash Of Clans | General |
| Cielo Owners Community | General |
| Clube Opel Centro | General |
| Center of Cool | General |
| Carens Owners Community | General |
| Continuums Of Care | General |
| Civilian Oversight Commission | General |
| Conventional Oxidation Catalyst | General |
| Citroen Owners Club | General |
| Corvette Owners Club | General |
| Chevrolet Owners Club | General |
| Cadillac Owners Club | General |
| Champion Of Champions | General |
| Chevrolet Owner Center | General |
| Challenge Of Champions | General |
| Cab Over Camper | General |
| Circuit Of Champions | General |
| Corvettes Of Choice | General |
| Corvettes Of Clarksville | General |
| Classic Corvette Club | General |
| Cobra Owners Club | General |
| Caterham Owners Club | General |
| Camping Oldie Club | General |
| Club Opel Corsa | General |
| Continuum of Care | General |
| Corolla Owners Club | General |
| Certificates of Confidentiality | General |
| Continuity of Care | General |
| Commission on Children | General |
| Clerk of Courts | General |
| Change Of Circumstances | General |
| Children of the Corner | General |
| Center of Concern | General |
| Coefficient Of Conservatism | General |
| Cash On Cash | General |
| Change of Command | General |
| Cycle of Concentration | General |
| Customer Originated Change | General |
| Customer Order Confirmation | General |
| Call of Cthulhu | General |
| Cast On Critical | General |
| Captains Of Crush | General |
| Creation Of Creators | General |
| City Of Cochem | General |
| Carrier Owned Container | General |
| Crucible Of Carnage | General |
| Control Of Corruption | Governmental |
| Corruption of | Governmental |
| Comptroller of the Currency | Governmental |
| Clash Of Clans | Governmental |
| Campaign Of Carnage | Governmental |
| Central Office Collection | Governmental |
| Chain-of-Custody | International |
| Círculos Obreros Comunistas | International |
| Corruption Of Champions | Internet |
| Clash Of Clan | Internet |
| Combined Oral Contraceptive | Medical |
| Combined Oral Contraceptive Pill | Medical |
| codein cups | Medical |
| Commission on Cancer | Medical |
| Cost of Care | Medical |
| Care Oncology Clinic | Medical |
| Communication, Orientation and Coordination | Medical |
| Communication, Orientation, Coordination. | Medical |
| Change Of Cast | Medical |
| Combat Operations Center | Military and Defence |
| Circle of Confusion | Military and Defence |
| Chain of Command | Military and Defence |
| Corps Operations Center | Military and Defence |
| Chart Overlay Copier | Military and Defence |
| Council of Colonels | Military and Defence |
| Captain of Communications | Military and Defence |
| City Of Chicago | Regional |
| Close-open-close | Space Science |
| Canadian Olympic Committee | Sports |
| Champions of Champions | Sports |
| Clerk of The Course | Sports |
| Cleveland Open Cup | Sports |
| Carrier of Carriers | Telecommunication |
| Central Office Connection | Telecommunication |