Technology glossary

Crown Group

A group containing the last common ancestor of all living members of a lineage and every descendant of that ancestor.

Cryogenic Control Electronics

Electronic circuits designed to generate, route or measure control signals while operating at extremely low temperatures near quantum processors. Placing control closer to qubits can reduce wiring, but the circuits must limit heat and electrical noise.

Cryogenic Dark Matter Detector

A detector operated at extremely low temperature to measure tiny energy deposits that could be produced by dark matter interactions.

Cryogenic Electronics

Electronic circuits designed to operate at very low temperatures, often near quantum processors or scientific sensors.

Cryptic Species

A species that is genetically or reproductively distinct from another species but looks so similar that conventional visual identification may not separate them reliably.

CubeSat

A standardized small satellite built from modular units measuring roughly ten centimetres per side.

Current Density

Electric current divided by electrode area, commonly expressed in amperes per square centimetre and used to compare the reaction rate or throughput of electrochemical devices.

CXCL9(CXCL9)

A chemokine that helps attract activated T cells, including cytotoxic CD8-positive T cells, toward tissues where an immune response is needed.

Cyber Attribution

The evidence-based process of identifying the person, group or state responsible for a cyber operation.

Cyborg Insect

A living insect fitted with electronic interfaces or payloads that allow humans or algorithms to guide or extend its natural abilities.

Cyclodextrin

A ring-shaped carbohydrate built from glucose units. Its cavity can host selected molecules or ions, so cyclodextrins are used in foods, medicines and materials engineering to carry, stabilize or confine chemical compounds.

Cytokine

A small signaling protein released by cells, especially immune cells, to coordinate inflammation, immune responses, cell growth and communication between tissues.

Dark Matter

An invisible form of matter that neither emits nor absorbs light, detected only through its gravitational effects on stars, gas, and light, and thought to make up most of the matter in the universe.

Data Annotation

The process of adding labels or structured information to raw data so it can be used to train or evaluate machine-learning systems. Examples include marking objects in images, identifying speakers in audio, or classifying the meaning of text.

Data Assimilation

The process of combining recent observations from satellites, weather stations, aircraft and other sources with a numerical model to estimate the atmosphere's current state. This estimated state becomes the starting point for a weather forecast.

Data Breach Notification

A formal report sent to a data-protection authority or affected people after an organization discovers a qualifying personal-data breach. Notification rules usually specify deadlines and required facts, but submitting a notice does not mean the regulator has completed an investigation or confirmed every allegation.

Data Center Water Use

Water consumed directly for cooling or indirectly through electricity generation and equipment manufacturing for data centers.

Data Safety Monitoring Board(DSMB)

An independent group that periodically reviews accumulating clinical-trial data for participant safety, study integrity and evidence that a trial should continue, change or stop.

Dataset Shift

A change between the data used to train a model and the data it encounters after deployment. This difference can reduce accuracy even when the model performed well during testing.

Dead Reckoning

Dead reckoning estimates a current position from a previously known position using measured speed, direction and elapsed time. Modern navigation systems often use it with inertial sensors to continue estimating movement when GNSS signals are temporarily unavailable.

Debris Disk

A circumstellar disk of dust and small bodies produced mainly by collisions among asteroids, comets, or planetesimals after the main planet-forming gas has dispersed. Its structure can provide clues about the architecture and evolution of a planetary system.

Deep Brain Stimulation(DBS)

A therapy that uses implanted electrodes to deliver electrical pulses to specific brain regions.

Default Time Limit

A preconfigured cap on service use that applies automatically unless an authorized person changes it.

Defense in depth

A security strategy that combines several independent or overlapping controls so that the failure of one layer does not expose the protected system. Layers may include isolation, access control, monitoring, network filtering and incident response.

Dendrite Formation

The growth of narrow, branch-like deposits on an electrode during repeated electrochemical plating and stripping. In metal batteries, dendrites can consume active material, reduce performance, pierce separators, and cause internal short circuits or safety failures.

Deorbit Burn

A deliberate engine firing that lowers a spacecraft's orbit so atmospheric drag brings it toward reentry. Mission controllers aim the maneuver at an approved corridor or remote disposal area. Its timing and direction determine where the vehicle encounters denser air and where surviving debris may fall.

Device Access Restriction(DAR)

A technical control that limits who can activate or use a product, often through age or identity verification, pairing, geofencing or another authorization step.

Device Provisioning

The process of registering a device and securely installing the identifiers, keys and configuration it needs to join a network.

Diagnostic Yield

The proportion of diagnostic procedures that produce enough reliable information to establish a specific diagnosis.

Differential diagnosis

A ranked set of diseases or conditions that could explain a patient's signs and symptoms. Clinicians narrow the list by gathering history, performing examinations and ordering tests whose results increase or reduce the likelihood of each possibility.