| MAchine-Readable Cataloguing | Academic & Science |
| Mobile Amateur Radio Corps | Academic & Science |
| Milton Area Racing Circuit | Academic & Science |
| Meat Animal Research Center | Academic & Science |
| Mid-America Regional Council | Academic & Science |
| Michigan Aeronautical Research Center | Academic & Science |
| Minority Access To Research Centers | Academic & Science |
| Mid-Atlantic Amateur Radio Club | Academic & Science |
| Mindful Awareness Research Center | Academic & Science |
| Mast Antenna And Rotator Calculator | Business |
| Marketing, Advertising, Research, and Communications | Business |
| Minority Access to Research Careers | Business |
| Marketing Authority Redefining Creativity | Business |
| Marlon Arbela Restaurant Corporation | Business |
| Madison Area Rehabilitation Centers | Community |
| Monroe Association For Retarded Citizens | Community |
| Missionary Athlete Recruitment Campaign | Community |
| Marin Association Of Retarded Citizens | Community |
| Midwest Area River Coalition | Community |
| Membership Application Review Committee | Community |
| Moab Arts and Recreation Center | Community |
| Monroe Association for ReMARCable Citizens | Community |
| Migration Acquisition Retention And Capitalization | Computing |
| Multiple Area Readout Computer | Computing |
| Machine Readable Cataloging | Computing |
| Metropolitan Area Retard Commuters | General |
| Many Aliens Record Contract | General |
| Men Advocating Real Change | General |
| Missionary Aviation Repair Center | General |
| Marion Animal Resource Connection | General |
| Midwest Association for Race Cars | General |
| Maintenance And Repair Contract | General |
| Modular Adaptive Robust Control | General |
| Manually Adjusted Ride Control | General |
| Mcmaster University Automotive Resource Centre | General |
| Model A Restorers Club | General |
| Musee Automobile Reims Champagne | General |
| Marcos | General |
| MAnpower Requirements Criteria | Governmental |
| Muti-technology Automated Reader Card | Governmental |
| Multi-technology Automated Reader Card | Governmental |
| Maryland Area Rapid Commuter | Governmental |
| Mobile Area Resource Centre | Governmental |
| Mid Altitude Radial Convergence | Governmental |
| Multiple Access Reservation Centre | Governmental |
| Marine Animal Rescue Coalition | Medical |
| Maryland Area Regional Commuter | Regional |
