| Acronym | Meaning |
| MCQDT | Multichannel Quantum Defect Theory |
| MCQR | Multiconfigurational Quadratic Response |
| MCR | Max. Continuous Rating |
| MCR | Metabolic Clearance Rate |
| MCR | Microcarbon Residue |
| MCR | Minimum Creep Rate |
| MCR | Multivariate Curve Resolution |
| MCR | Mutual Climate Range |
| MCRG | Monte Carlo Renormalization Group |
| MCRHF | Multiconfigurational Relativistic Hartree-Fock |
| MCRPA | Multiconfigurational Random Phase Approxn. |
| MCRRPA | Multiconfiguration Relativistic Random Phase Approxn. |
| MCRT | Mean Cell Residence Time |
| MCS | Monte Carlo Simulation |
| MCS | Management Control System |
| MCS | Media Cleanup Standard |
| MCS | Multiple Cloning Site |
| MCSCF | Multi Configuration Self Consistent Field |
| MCSCO | Multiconfiguration Self-consistent Orbital |
| MCSCRF | Multiconfigurational Self-consistent Reaction Field |
| MCSF | Macrophage Colony Stimulating Factor |
| MCSTEP | Multiconfigurational Spin-tensor Electron Propagator |
| MCSX | Multiconfiguration Single Excitation |
| MCT | MOS Controlled Thyristor |
| MCT | Mercury Cadmium Telluride |
| MCTDH | Multiconfigurational Time-dependent Hartree (theory) |
| MCTDH/BSE | MCTDH (with) Basis Set Expansion |
| MCTDHF | Multiconfiguration Time-dependent Hartree-Fock |
| MCV | Mean Corpuscular Volume |
| MCV | Mesoscale Convective Vortex |
| MCVD | Modified Chemical Vapor Deposition |
| MCVP | Metal Chemical Vapor Deposition |
| MCWF | Monte-Carlo Wave Function (method In Study Of Dissipative Processes In Quantum Optics) |
| MCXD | Magnetic Circular X-ray Dichroism |
| MCY | Matsuoka-Clementi-Yoshimine (potential Function) |
| MCZDO | Many Center Zero Differential Overlap |
| MD/MC-CEM | Molecular Dynamics/Monte Carlo-corrected Effective Medium |
| MDA | Metal Deactivator |
| MDBK | Madin-Darby Bovine Kidney |
| MDC | Maxwell Displacement Current |
| MDC | Macrophage Derived Chemokine |
| MDC | Minimum Detectable Concentration |
| MDCB | Methods And Data Comparability Board |
| MDCK | Madin-Darby Canine Kidney |
| MDD | Maximum Daily Dose |
| MDEQ | Michigan Department Of Environmental Quality |
| MDF | Medium-density Fiberboard |
| MDGC | Multidimensional Gas Chromatography |
| MDGI | Mammary Gland-derived Growth Inhibitor |
| MDH | Malate Dehydrogenase |