| Acronym | Definition |
|---|
| MACS | Macintosh System (creator code on system files) |
| MACS | Mobile Air Conditioning Society |
| MACS | Mathematics and Computer Science |
| MACS | Mathematical and Computer Sciences |
| MACS | Marine Air Control Squadron |
| MACS | Modular Artillery Charge System (US Army) |
| MACS | Maryland Association of Community Services |
| MACS | Multi Agency Coordination System |
| MACS | Minnesota Association of Charter Schools |
| MACS | Mobile Approach Control System |
| MACS | Master of Arts in Christian Studies |
| MACS | Magnetic Active Compensation System |
| MACS | Multipurpose Arcade Combat Simulator |
| MACS | Modem Access Control System |
| MACS | Microsoft Audit Collection System |
| MACS | Massive Cluster Survey |
| MACS | Money Advice and Community Support Service (Brighton, East Sussex, UK) |
| MACS | Manufacturing Application Control System |
| MACS | Maximum Adjacent Cut Specification (locksmithing) |
| MACS | Senior Chief Master-at-Arms (US Navy) |
| MACS | Michigan Association of Convenience Stores |
| MACS | Medium Access Control Sublayer |
| MACS | Member of Australian Computer Society |
| MACS | Mutually Agreeable Commercial Software |
| MACS | Multiple Access Communications System |
| MACS | Mail Order and Catalog System |
| MACS | Mac Asheville Computer Society |
| MACS | Mapping Application Client/Server |
| MACS | Mid-Atlantic Cooperative Services LLC (electric power company) |
| MACS | Mid-America Cable Show |
| MACS | Multilink Access Control Systems (UK) |
| MACS | Manitoba Academy of Chinese Studies |
| MACS | Major Apparatus and Cable System |
| MACS | Manipulation and Beam Collimation System |
| MACS | Modified Atomic Charge Superposition |
| MACS | Manned Air Combat Simulator |
| MACS | Middle Atmosphere in the Climate System |
| MACS | Multiline Automatic Calling System |
| MACS | Modular Digital Altitude Control System |
| MACS | Mobile Ash Conditioning System |
| MACS | Mobile Armored Crew Station |
| MACS | Master Alert Control Station |
| MACS | Senior Chief Machine Accountant (US Navy rating) |
| MACS | Medicare Automated Claims System |
| MACS | Magnetic-Activated Cell Separation |
| MACS | Make A Child Smile (Sunrise, FL; charity organization) |
| MACS | Mansfield Adult CoEd Soccer (Texas) |
| MACS | Master of Arts in Communication Studies (various schools) |