| Acronym | Definition |
|---|
| MOS | Months |
| MOS | Military Occupational Specialty (US Army) |
| MOS | Metal-Oxide Semiconductor |
| MOS | Microsoft Office Specialist |
| MoS | Ministry of Sound (London Night Club) |
| MOS | Mates of State (band) |
| MOS | Museum of Science (Boston, MA) |
| MOS | Mambo Open Source |
| MOS | Mean Opinion Score |
| MOS | Margin of Safety |
| MOS | Manual of Style (Wikipedia article style guide) |
| MOS | Moment of Silence |
| MOS | Medical Outcomes Study |
| MOS | Military One Source (US DoD) |
| MOS | Model Output Statistics |
| MOS | Man of Steel (aka The Man of Steel; also seen as TMOS) |
| MOS | Made of Steel |
| MOS | Metal-Oxide-Silicon |
| MOS | Man On the Street (type of interview) |
| MOS | Media Object Server |
| MOS | Maintenance Operations Squadron |
| MOS | Marine Observation Satellite |
| MOS | Monthly Operational Summary |
| MOS | Mom over Shoulder (texting; aka Mother over Shoulder) |
| MOS | Medical Office Specialist |
| MOS | Member of the Opposite Sex |
| MOS | Multi-Object Spectrograph |
| MOS | Macintosh Operating System |
| MOS | Maryland Ornithological Society (Baltimore, MD) |
| MOS | Multi-Object Spectrometer |
| MOS | Management Operating System |
| MOS | Mother of Sorrows (New York Catholic school) |
| MOS | Make Out Session |
| MOS | Member of the Service (NYPD Sworn Officer) |
| MOS | Mittelstandskinder Ohne Strom (band, German: Middle-Class Children Without Energy) |
| MOS | Member of Service (police) |
| MoS | Manual of Standards |
| MOS | Mic-O-Say (Honor Camping Society of the Heart of America Council, Boy Scouts of America) |
| MOS | Mic-O-Say (Tribe) |
| MOS | Major Operating System |
| MOS | Major Orthopedic Surgery |
| MOS | Multi-Beam Optical Sensor |
| MOS | Matter of Size |
| MOS | Michael O'Neal Singers (Roswell, GA) |
| MOS | Margin on Services (insurance) |
| MOS | Marineoperationsschule (German Navy school) |
| MOS | Military Occupation Skill |
| MOS | Minimum Operating Strip |
| MOS | Method of Statement |
| MOS | Michigan Orchid Society (Ann Arbor, MI) |
| MOS | Mini Operating System |
| MOS | Method Of Supply |
| MOS | Mode Of Shipment |
| MOS | Metal Oxide Substrate |
| MOS | Material On Site |
| MOS | Mobility Operations School |
| MOS | Massachusetts Orchid Society |
| MOS | MIDS on Ship (Multifunctional Information Distribution System) |
| MOS | Mountain Ocean Sea (Japanese burger chain) |
| MOS | Maintenance Out of Service |
| MOS | Mother of Our Savior (Detroit, MI grade school, now defunct) |
| MOS | Military Operations Specialist (FAA) |
| MOS | Maritime Observation Satellite |
| MOS | Mute on Sound |
| MOS | Motion Omit Sound (TV term for silent film or tape) |
| MOS | Manned Orbital Station |
| MOS | Minimum Operational Sensitivity |
| MOS | Maintenance Override Switch |
| MOS | Marked Out of Stock |
| MOS | Management Operations Staff |
| MOS | Marine Occupational Standard |
| MOS | Manual Observing System |
| MOS | Military Oceanography Subcommittee |
| MOS | Malibu Orchid Society, Inc. |
| MOS | Mapping Ocean Sanctuaries (Center for Image Processing in Education) |
| MOS | Mit Out Sprechen/Sound (without speech; German/English movie term for shot without dialog) |
| MOS | Measure Of Suitability/Stability |
| MOS | Minus Optical Strip (acting) |
| MOS | Material Ordering Schedule |
| MOS | Materials Ordering System |
| MOS | Military Obligated Service |
| MOS | Modulated Orthogonal Sequence |
| MOS | Monitor Only Stations |
| MOS | Main Object Size |
| MOS | Mission Operational Specialty |
| MOS | Morph Operating System |
| MOS | Multifunctional Operator System |
| MOS | Multiplex Out of Sync (Hekimian) |
| MOS | Manually Out of Service |
| MOS | Modetti Office Services (Singapore) |