Technology Glossary

Hydrothermal Fluid

Hot, mineral-rich water that circulates through fractures in rock, usually heated by magma or residual geothermal energy. As it cools or reacts with the rock, it can dissolve, transport and deposit minerals that preserve evidence of past underground water systems.

Hyperglycemia

A higher-than-normal level of glucose in the blood, common in uncontrolled diabetes and prediabetes, linked to a range of health risks including some cancers.

Hyperscale Data Center

A very large computing facility designed to scale rapidly across vast numbers of servers, storage systems, and network devices. It typically uses standardized, automated infrastructure to support cloud platforms, internet services, or AI workloads, with substantial power, cooling, water, and land requirements.

Ice Dynamical Imbalance

A mismatch between the amount of ice supplied to glaciers and the amount they discharge, often expressed when faster flow sends more solid ice across the grounding line into the ocean.

Ice Sheet Mass Balance

The net change in an ice sheet's mass after accounting for gains such as snowfall and losses such as surface melt, basal melt and solid ice flowing into the ocean.

Ice-Supersaturated Region(ISSR)

A cold atmospheric region where humidity relative to ice exceeds saturation, allowing ice crystals and persistent contrails to survive and grow. Contrail-avoidance systems try to forecast and route aircraft around these moving zones.

Idiopathic Pulmonary Fibrosis(IPF)

A chronic disease in which lung tissue becomes progressively scarred for no known cause, making breathing and oxygen transfer increasingly difficult. Treatments can slow decline for some patients, but they do not reliably reverse established scarring.

Imaging Spectrometer

An imaging spectrometer measures light at multiple wavelengths for locations across an image. Its spectra help distinguish substances through their characteristic absorption patterns. In satellite greenhouse-gas monitoring, this allows analysts to locate gas plumes. Detecting a gas and estimating its emission rate are separate tasks; atmospheric conditions can limit both.

Immune Checkpoint Inhibitor

A cancer therapy that blocks inhibitory signals used by tumors to suppress immune attack.

Immune Checkpoint Therapy

A form of cancer immunotherapy that blocks inhibitory signals, such as PD-1, PD-L1, or CTLA-4, that can restrain T cells. Releasing these checkpoints may help the immune system attack tumors, but it can also cause inflammatory side effects in healthy organs.

Immunosenescence

Age-related changes that reduce some immune functions while increasing chronic inflammation.

Impact Winter

A period of severe global cooling that may follow a very large asteroid or comet impact. Dust, soot, and aerosols injected into the atmosphere can block sunlight, disrupt photosynthesis, and alter climate and food systems for months or longer.

In Silico Screening

The use of computational models to prioritize or reject candidate molecules before laboratory testing.

In Vivo Gene Editing

In vivo gene editing means performing a genetic edit directly inside a patient’s body rather than removing cells, editing them in a laboratory, and returning them. The editing machinery is delivered to the target tissue, often using a viral vector or a lipid nanoparticle, where it modifies DNA in selected cells.

In-Memory Computing

A computing approach that performs operations where data is stored, reducing movement between processors and memory.

In-Situ Drug Delivery

Administering a medicine directly at the location where a patient or target is found rather than transporting them first.

In-situ Friction Stir Forging

A solid-state manufacturing process in which a rotating tool heats, deforms and consolidates material through friction and pressure. In powder processing, it can bond particles into a dense part without fully melting them.

In-Situ Resource Utilization(ISRU)

The practice of obtaining useful materials such as water, oxygen or fuel from resources found at an exploration destination rather than carrying everything from Earth.

Independent Compliance Audit

An external review that tests whether an organization is meeting specified legal or contractual requirements.

Indicator of Compromise(IoC)

Observable evidence that may signal a system or network has been attacked, such as a malicious domain, file hash, unusual process, registry change, or suspicious connection pattern.

Indirect bandgap

An indirect bandgap is an electronic structure in which an electron transition between the band edges also requires a change in crystal momentum, usually supplied by a lattice vibration called a phonon. Light absorption and emission are therefore less probable near the band edge, but charge carriers can persist longer before radiative recombination.

Induced Pluripotent Stem Cell(iPSC)

A mature cell reprogrammed into a stem-cell-like state that can develop into many different cell types.

Induction Effect

A wider economic change caused when a new technology alters production possibilities, investment or demand, creating activities and emissions that would not have existed under the previous technology and cost structure.

Industrial Control System(ICS)

A combination of controllers, networks, software and operator interfaces used to manage an industrial or infrastructure process.

Industrial Espionage

The covert acquisition or disclosure of confidential commercial or technical information to benefit another company, organisation or state. It can involve insiders, cyber intrusion, deceptive recruitment or physical collection, and may be prosecuted under espionage, trade-secret or industrial-technology laws depending on the facts.

Inertial Confinement Fusion(ICF)

A fusion approach that uses lasers, particle beams, or another driver to compress and heat a tiny fuel capsule so quickly that the fuel's own inertia briefly keeps it confined while fusion reactions occur.

Inertial Measurement Unit(IMU)

An electronic sensor unit that measures motion and orientation using accelerometers and gyroscopes, and sometimes magnetometers. Its readings help estimate a device's acceleration, angular velocity, and attitude without relying solely on external positioning signals.

Technology glossary