| Acronym | Definition |
|---|
| HAC | Hearing Aid Compatible |
| HAC | Hill-Start Assist Control (automobiles) |
| HAC | Housing Assistance Council |
| HAC | Home Access Center |
| HAc | Acetic Acid |
| HAC | Honourable Artillery Company |
| HAC | Health Action in Crises (UN World Health Organization) |
| HAC | House Appropriations Committee |
| HAC | Havre Athletic Club (Le Havre, France) |
| HAC | Health Administration Center (US VA) |
| HAc | Acetaldehyde |
| HAC | Humanitarian Aid Commission |
| HAC | Hospital Acquired Condition |
| HAC | Human Artificial Chromosome |
| HAC | Hearing Aid Council |
| HAC | Hyperadrenocorticism |
| HAC | High Alumina Cement |
| HAC | Humanist Association of Canada |
| HAC | Haiti Action Committee (Berkeley, CA) |
| HAC | Helicopter Aircraft Commander |
| HAC | Hydrogen-Assisted Cracking |
| HAC | Heinous, Atrocious, and Cruel (crime categorization) |
| HAC | Hot Action Cop (band) |
| HAC | Hybrid Adaptive Caching |
| HAC | Hazardous Area Classification |
| HAC | Humanitarian Affairs Commission |
| HAC | Hockessin Athletic Club (Hockessin, DE) |
| HAC | Heading Alignment Circle (NASA; space shuttle) |
| HAC | Homeless Action Center (legal services agency, Berkeley California) |
| HAC | Heavy Assault Cruiser (gaming, EVE Online) |
| HAC | Hamilton Arts Collective (Baltimore, MD) |
| HAC | Hydrogenated Amorphous Carbon |
| HAC | Higher Authority Communications |
| HAC | High Altitude Compensator |
| HAC | High Altitude Compensation |
| HAC | Have A Cow |
| HAC | Hughes Aircraft Corporation |
| HAC | Hmong American Community |
| HAC | High Angle Conveyor |
| HAC | Hot Asian Chick |
| HAC | Hybrid Aircraft Corporation (Edgewood, NM) |
| HAC | Human Assurance Committee (Medical College of Georgia) |
| HAC | Health Assessment Questionnaire (used to assess quality of life) |
| HAC | Heparin Affinity Chromatography |
| HAC | Hydroxyapatite Ceramics |
| HAC | Heteroscedasticity Autocorrelation-Consistent |
| HAC | Hydroxyapatite Chromatography |
| HAC | Host America Corporation |
| HAC | High Acceleration Cockpit |
| HAC | Hollywood Advisory Council |
| HAC | Harbor and Approach Chart |
| HAC | Help the Afghan Children |
| HAC | Hawaii Air Cargo (Honolulu, HI) |
| HAC | Hansard Association of Canada |
| HAC | HIDTA Assistance Center |
| HAC | High Availability Component |
| HAC | Hierarchical Aglomerative Clustering (datamining) |
| HAC | Humanitarian Area Coordinator |
| HAC | Homeland Acquisition Corporation (Oklahoma City, OK) |
| HAC | High Accumulator (USAF SACCS 465L EDTCC SPE) |
| HAC | Hot Athletic Chick |
| HAC | Hudson Associates Consulting, Inc (Virginia Beach, VA) |
| HAC | Head Ally Cockroft (Australian-based consulting firm) |
| HAC | Hawaii Advisory Committee (USCCR) |
| HAC | Housing Advice Centre (various locations) |
| HAC | Health Access Coalition |
| HAC | Houston Area Council (American Business Women's Association; Texas) |
| HAC | High Availability Clustering (computing) |
| HAC | Home Affairs Committee (UK) |