| Abbreviation | Definition |
|---|---|
| HDW | Vector graphics (Harvard Draw) |
| HDX | Help index (AutoCAD - Zortech C++) |
| HED | Document (HighEdit) |
| HEL | Game data (Microsoft Hellbender) |
| HEP | Novell Help Librarian Data File (Novell NetWare) |
| HEX | HEX dump |
| HEX | Macintosh BinHex Encoded file archive (ASCII) |
| HFI | Hewlett-Packard Font Information file |
| HGL | Highlight groups definitions (DN) |
| HGL | Vector graphics (HP Graphics Language) |
| HH | C++ header file |
| HHH | Precompiled header file (Power C) |
| HHP | Procomm Plus Help information for remote users |
| HI | High scores (games) |
| HIG | High scores (games) |
| HIN | Molecule (HyperChem) |
| HIPO | Hierarchy Input Process Output |
| HIPS | Bitmap graphics (HIPS file) |
| HIS | History of executing/ viewing/ editing |
| HLB | Help library (VMS) |