| TP4 | OSI Transport Protocol Class 4 [Error Detection and Recovery Class] |
| TP0 | OSI Transport Protocol Class 0 [Simple Class] |
| F | first class |
| NIHCL | NIH Class Library |
| RFC | Response For a Class |
| COS | Class of Service |
| UNC | Unbalanced Normal Class |
| SmCL | Smart Class Loader |
| CQM | Class Queue Management |
| TP0 | Transport Protocol Class 0 [OSI] |
| CCD | Class Communication Diagram |
| TP4 | Transport Protocol Class 4 [OSI] |
| UAC | Unbalanced Asynchronous Class |
| CLO | Class Option [LaTeX] |
| CDS | Class Data Sharing |
| FEC | Forward Equivalence Class |
| BAC | Balanced Asynchronous Class [engl.] |
| BAC | Balanced Asynchronous Class [engl.] Betriebsart von HDLC |
| CRC | Class, Responsibility, Collaboration/Collaborators |
| DBI | Data Base Interface [Class] |
| AFC | Application Foundation Class [engl.] Programm-Modul für Java |
| LLC2 | Logical Link Control Class 2 |
| CAD | Class Association Diagram [engl.] |
| CBQ | Class Based Queueing [engl.] Warteschlangen mit unterschiedlichen Prioritäten |
| PAM-D | Payload Assist Module, Delta-class |
| BCVT | Basic Class Virtual Terminal [engl.] |
| int. | international [dt.] |
| KI | Kiwanis International |
| Environ. Int. | Environment International Zeitschrift |
| IU | International Unit |
| IXI | International X.25 Interconnect |
| iX | International Exchanges |
| IES | International EPR Society |
| NI 200 | DMV International GmbH Nörten-Hardenberg, Niedersachsen |
| IS | International Standard [ISO] |
| is | International Standard |
| GNI | GayNet International |
| IA | International Alphabet |
| INN | International Non-proprietary Name |
| TI | Transparency International e.V. Berlin, http://www.transparency.de |
| UI | Unix International |
| INC | International Carrier |
| IAD | Dulles International Washington DC |
| intl. | international [engl.] |
| ISP | International Standardized Profile |
| ICJ | International Court of Justice |
| IEC | International Engineering Consortium |
| ICE | International Cometary Explorer |
| IOM | International Office of Migration |
| ISEE | International Sun Earth Explorer |