sort by Rank | Alpha
| Possible Meanings | Rank |
| High Explosive, Dual Purpose | *** |
| 186Re-(tin)1,1-hydroxyethylidene diphosphonate | ** |
| 186Re-1,1-hydroxyethylidene diphosphonate | ** |
| Halma Executive Development Programme | * |
| Hanford External Dosimetry Program | * |
| Human Exploration Demonstration Project | * |