| HD | High Definition |
| GD | Geometric Definition |
| KDT | Key Definition Table |
| WOD | Web Object Definition |
| HDA | High Definition Audio |
| IOD | Information Object Definition |
| HDD | High Definition Display |
| OSD | Open Source Definition |
| HDS | High Definition System |
| IDL | Interface Definition Language |
| idt | Improved Definition Television |
| IDTV | Improved Definition Television |
| LADE | Language Definition Environment |
| DDS | Disk Definition Structure |
| LDTV | Limited Definition Television |
| DDS | Disk Definition Structure |
| ODL | Object Definition Language |
| DD | Data Definition/Deliverable |
| DMI | Definition Of Management Information |
| DTD | Document Type Definition |
| SVID | System V Interface Definition |
| WIDL | Web Interface Definition Language |
| SDTV | Standard Definition Television |
| FDL | File Definition Language |
| DDL | Data Definition Language |
| NIDL | Network Interface Definition Language |
| SVID | Unix System V Interface Definition |
| OIDL | Object Interface Definition Language |
| PDIF | Product Definition Interchange Format |
| ADTV | Advanced Definition Television [engl.] Verbesserter Fernsehstandard |
| NDDL | Neutral Data Definition Language |
| GDMO | Guidelines for the Definition of Managed Objects [OSI] |
| IDL | Interface/Internet Definition Language |
| HDCD | High Definition Compatible Digital |
| HDMI | High Definition Multimedia Interface |
| HDCP | High Definition Content Protection |
| CDF | Channel Definition Format [engl.] |
| DHDTV | Digital High Definition Television |
| EDTV | Enhanced/Extended Definition Television |
| EDL | Encapsulator/Enterprise Definition/Description Language |
| RTEID | Real Time Executive Interface Definition |
| PPD | Postscript Printer Definition / Description [Adobe] |
| I4DL | Interface, Inheritance, Implementation, Installation Definition Language |