| Subject | English | Thesaurus |
| abbr., proj.manag. | CD3 | certificate of deposit |
| abbr., logist. | CD3 | cubic decimeter (pelipejchenko) |
| abbr., oil | CD3DIA | card 3 diagnostic |
| abbr., microel. | C³L | complementary constant-current logic |
| abbr. | CO3 | Combined Staff Public and Governmental Affairs Officer |
| abbr., microel. | C³RAM | continuously charge-coupled random-access memory |
| IT | Energy-conscious 3D Server-on-Chip for Green Cloud Services Project | Eurocloud server project |
| abbr., physiol. | H2CO3 | Carbonic Acid |
| abbr., surg. | http://www.radiesse-fl.com/images/techniques_3.gif | marionette lines (drag) |
| abbr., chem. | K2CO3 | potassium carbonate (MichaelBurov) |
| chem. | K3Co NO26 | K3CO(NO2)6 |
| chem. | Li2CO3 | CO3Li2 |
| abbr., telecom. | 3M Co. | Minnesota Mining and Manufacturing Co. |
| abbr., file.ext. | Modula-3 Base program | B |
| law | Pa.Dist. & Co.3d. | Pennsylvania District and County Reports, Third Series |
| abbr. | 3rd party antivirus program | third-party antivirus program (ssn) |
