English abbreviations from ha to hac
- HA (Hospital Apprentice)
- HAA (Hasvik Airport)
- HAAP (Healthcare All-Access Project)
- HAARP (High Frequency Active Auroral Research Program)
- HAARS (High-Altitude Airdrop Resupply System)
- HAART (Highly Active Anti-Retroviral Therapy)
- HAB (Heavy Assault Bridge (US))
- HABD (Holiday Angel Blood Drive)
- HABIT (Health And Behaviours In Teenagers)
- HABTM (HasAndBelongsToMany)
- HAC (Hachijojima Airport (Hachijo Jima Airport))
- H-AC (Harley Allendale-Columbia "A DOOPLIKATION 'DUDE')