Technology glossary

Messenger RNA Vaccine(mRNA vaccine)

A vaccine that delivers messenger RNA instructions prompting cells to temporarily produce an antigen, which trains the immune system to recognize a target. The mRNA does not need to enter the cell nucleus and is broken down after delivering its instructions.

Meteorite Contamination Control

Procedures used to prevent, measure, and document the introduction of terrestrial material into a meteorite sample during recovery, handling, storage, and analysis. Controls can include clean tools, protective packaging, environmental blanks, chain-of-custody records, and comparisons with local soil or air.

Methalox

A rocket propellant combination of liquid methane fuel and liquid oxygen oxidizer. Methalox engines burn cleaner than kerosene-based ones, leaving less residue on reused hardware, and methane is seen as easier to produce on Mars than other rocket fuels.

Micro-Computed Tomography(microCT)

A high-resolution X-ray imaging technique that reconstructs the internal three-dimensional structure of small specimens. In nerve research it can reveal fascicles and other anatomical features without cutting every section first.

Microbial Upcycling

The use of microorganisms to convert low-value waste into chemicals, materials, fuels or food ingredients with greater practical value.

Microneedle Patch

A patch containing arrays of tiny needles that penetrate the outer skin with little or no pain to deliver drugs, vaccines, or collect biological fluid. Designs may use solid, coated, dissolving, hollow, or hydrogel-forming microneedles.

Microvascular Injury

Damage to the smallest blood vessels that supply an organ. In a transplant it can impair circulation, promote inflammation and gradually reduce graft function.

Mie Resonance

An optical resonance that occurs when light interacts with a particle whose size is comparable to its wavelength. The particle can then scatter selected wavelengths strongly, allowing dielectric nanoparticles to generate vivid structural colours.

Minimal Risk Condition

A safe state that an automated vehicle attempts to reach when it cannot continue normal driving, such as stopping in a suitable location.

Mirror Life

A hypothetical self-replicating form of life built from mirror-image versions of the chiral molecules used by ordinary biology. No complete mirror organism is known to exist, and proposed research controls focus on preventing its creation because its interactions with immune systems and ecosystems could be unusually difficult to predict or contain.

Mismatch Repair Deficiency(dMMR)

A condition in which cells cannot properly correct certain DNA-copying errors because the mismatch-repair system is impaired. It can cause microsatellite instability and a high mutation burden, occurs in several cancers, and may help predict response to some immunotherapies.

Mission Availability

The proportion of time a system is ready and able to perform its assigned mission, accounting for maintenance, repair, supply and operating conditions. A high fleet count does not guarantee high availability.

Mixture of Experts(MoE)

A machine-learning architecture made of multiple specialized subnetworks, called experts, and a routing mechanism that selects which experts process each input. Activating only part of the model can increase capacity without using every parameter for every request.

Model Context Protocol(MCP)

An open protocol that lets an AI application discover and use tools, data sources, and actions exposed by an external service through a standardized interface.

Model Distillation Attack

Unauthorized, large-scale collection of one AI model's outputs or protected reasoning to train another model to imitate its capabilities.

Model Hallucination

An output generated by an AI model that is false, unsupported, internally inconsistent, or presented with unjustified confidence. Hallucinations can arise even when language is fluent, so important claims should be checked against reliable evidence.

Model Hub

An online platform where developers publish, discover, version and download machine-learning models and related files.

Model Overreach

Behavior in which an AI model takes actions beyond the authority, scope or intent of the task it was given.

Model Refusal

A response in which an AI model declines to fulfill a user's request, usually because a safety rule, policy constraint, uncertainty threshold, or system instruction has been triggered. Refusals may be appropriate safeguards or, when overly broad, reduce usefulness.

Model Repository

A versioned collection containing an AI model’s weights, configuration, documentation and supporting code.

Model Weights

The numerical parameters learned during AI training that determine how a model transforms inputs into outputs. They encode much of a model's acquired capability, so access to them can allow copying, fine-tuning or deploying the model without the original developer's hosted service.

Molecular Electronics

A field that uses individual molecules or very thin molecular layers as active parts of electronic devices, such as switches, memories or sensors. Their electrical behavior can be adjusted through molecular structure, but reliable contacts and large-scale manufacturing remain difficult.

Molecular Glue

A small molecule that stabilizes an interaction between two proteins, or between a protein and another molecule, to alter a biological process that may otherwise be difficult to target.

Molecular Junction

An electronic structure in which one molecule or a molecular layer sits between two conductive electrodes. Researchers measure how charge moves through the molecules to study switching, memory, sensing and other nanoscale functions.

Morphometrics

The quantitative study of biological shape, size, and structural variation.

Mucus Plug

A dense accumulation of mucus that partially or completely blocks an airway. Mucus plugs can worsen airflow limitation, trap infection and contribute to symptoms or exacerbations in chronic lung disease.

Multi-Accelerator Support

Software compatibility that allows workloads to run on more than one family of AI accelerators rather than depending on a single vendor.

Multi-Constellation GNSS

Multi-constellation GNSS receivers track satellites from more than one navigation system, such as GPS, Galileo, BeiDou and GLONASS. More visible satellites can improve availability and geometry, especially in cities and difficult environments.

Multi-Effector Decoding

Multi-effector decoding is the simultaneous interpretation of neural signals associated with more than one body output, such as speech and hand or facial movement. It is harder than decoding each output separately because their brain representations can overlap and one action can alter the signal produced by another. Training on combined actions can help a model distinguish concurrent intentions.

Multi-Messenger Astronomy

The study of one cosmic source or event using more than one signal type, such as light, neutrinos, cosmic rays or gravitational waves. Combining messengers can reveal different physical processes.