| Acronym | Definition |
|---|
| ACH | Automated Clearing House |
| ACH | Alcohol |
| ACH | Arkansas Children's Hospital (Little Rock, AR) |
| ACH | Air Changes per Hour (ventilation) |
| ACH | Acetylcholine |
| ACH | Association for Computers and the Humanities |
| ACH | Adult Care Home |
| ACH | Anything Can Happen (various meanings) |
| ACH | Analysis of Competing Hypotheses (intelligence analysis) |
| ACH | Achondroplasia |
| ACH | All Children's Hospital (St. Petersburg, FL) |
| ACH | Authentic Custom Homes |
| ACH | Access Feedback Channel |
| ACH | Auckland City Hospital (New Zealand) |
| ACH | Aluminium Chlorohydrate (salts) |
| ACH | Automotive Components Holdings (various locations) |
| ACH | Advanced Combat Helmet |
| ACH | Acute Care Hospital (various locations) |
| ACH | Access Channel |
| ACH | Academic Credit Hours |
| ACH | Allen County Hospital (Iola, KS) |
| ACH | Army Community Hospital |
| ACH | Aircraft Hangar (USAF bare base deployable aircraft shelter) |
| ACH | Angeles Crest Highway (California SR2) |
| ACH | Association of Children's Hospices (UK) |
| ACH | Area Combined Headquarters |
| ACH | Armada de Chile (Spanish: Chilean Navy) |
| ACH | A Concentrated High (coagulant) |
| ACH | Adrenal Cortical Hormone |
| ACH | Alice Cook House (Cornell University; New York) |
| ACH | American College of Heraldry |
| ACH | Automated Charge |
| ACH | Attempts per Circuit per Hour |
| ACH | Association Coopération Humanitaire (French: Humanitarian Cooperation Association; est. 1992) |
| ACH | Agent Charge (freight forwarding) |
| ACH | American Clearinghouse |
| ACH | Above Counter Height (construction blueprints) |
| ACH | Assault Craft Helmet (Gentex) |
| ACH | Antenna Selection Reference Signal Channel |
| ACH | Adler-Coppersmith-Hasner (algorithm) |
| ACH | ACCS Common Hardware |
| ACH | Average Call Handle (time; call center metric) |
| ACH | Alpha-Cellulose Hydrolysis |