| Acronym | Definition |
|---|
| HDD | Hard Disk Drive |
| HDD | Horizontal Directional Drilling |
| HDD | Hyderabad (Pakistan) |
| HDD | Heating Degree Days (weather derivatives / insurance index converting temperature into prices) |
| HDD | Hickory Dickory Dock (nursery rhyme) |
| HDD | Hospital de Día (Spanish: Day Hospital) |
| HDD | Heavy-Duty Diesel |
| HDD | High Definition Display |
| HDD | High Definition Decoder |
| HDD | High Density Disk |
| HDD | Human Development Department (World Bank) |
| HDD | Harry the Dirty Dog (book) |
| HDD | Hard Drive Division (various companies) |
| HDD | Head-Down Display |
| HDD | Head Down Display |
| HDD | High Density Data |
| HDD | Hearing Dogs for the Deaf (UK) |
| HDD | Heavy Drinking Day (alcohol dependence) |
| HDD | High Density Diskette |
| HDD | Hot Diggity Dog |
| HDD | Hard Decision Decoding |
| HDD | Health Data Dictionary |
| HDD | Highly Doped Drain |
| HDD | Holographic Disk Drive |
| HDD | Hrvatski Dalmatinski Dom (Croatian Dalmatian Home, political party) |
| HDD | Hardware Design Document |
| HDD | Human Disorientation Device |
| HDD | Hierarchical Data Dictionary |
| HDD | Hammer Debounce Device (airguns) |