Technology glossary

Operational Weather Model

A forecasting model run routinely on a fixed schedule with real-time observations and quality controls to support official weather services and decisions.

Opsin

A light-sensitive protein that changes shape after absorbing light and can trigger or modulate a biological signal.

Optical Player Tracking

A camera-based system that estimates player and ball positions continuously during a match.

Optogenetics

A research method that uses genetically introduced light-sensitive proteins to control the activity of selected cells with light, especially neurons.

Optomechanical Surface

A surface whose visible optical behavior changes through controlled mechanical movement. It combines structures that guide light with parts that slide, rotate or deform to select a visual state.

Orbital Insertion

The maneuver that gives a spacecraft enough horizontal velocity to enter its intended orbit rather than falling back to Earth. Reaching space above a chosen altitude is not sufficient unless the vehicle also achieves the required speed and direction.

Orbital Launch Vehicle

A rocket-powered vehicle designed to carry a payload from Earth into orbit. It may use one or more stages that separate during flight to reduce mass and reach the speed and altitude required for orbit.

Orbital Propagation

The mathematical calculation of an object's future or past position from observations of its orbit. Accurate propagation must account for gravity, solar radiation pressure and measurement uncertainty, especially for distant or tumbling objects.

Orbital Reflector

An object placed in orbit and designed to reflect sunlight toward Earth or another target. Proposed uses include illumination, signaling, and experiments, but large or bright reflectors may create space-debris, astronomical-observation, environmental, and governance concerns.

Origin-Bound Authentication

Authentication whose cryptographic response is valid only for the intended website or application origin. Passkeys and hardware security keys use this property to resist credential replay on lookalike phishing sites.

Out-of-Distribution Generalization(OOD generalization)

A model's ability to perform reliably on data that differs meaningfully from the distribution represented in its training set. It tests whether the model learned transferable patterns rather than relying only on correlations specific to familiar conditions.

Outer Radial Glia

A subtype of radial glial progenitor abundant in the developing human cortex. Its capacity for repeated division is associated with expansion and folding of the cerebral cortex.

Over-the-Air Update(OTA)

Software delivered wirelessly to a connected vehicle or device without a workshop visit. It can change control behavior and add safety responses, but it cannot replace a physical component when the hardware itself needs redesign.

Overall Survival(OS)

The time from a defined starting point, such as randomization or treatment initiation, until death from any cause. It is a direct clinical-trial endpoint, although results can take a long time to mature and may be influenced by treatments received after the study intervention.

Oxidative Hydrothermal Dissolution

A treatment that uses water and oxygen at elevated temperature and pressure to break resistant organic materials into smaller molecules that microbes or chemical processes can use.

Oxygen Evolution Reaction(OER)

The electrochemical step in which oxygen atoms combine and are released as gas at an electrode, the reaction that occurs when a solid oxide or electrolysis cell splits water to produce hydrogen.

Oxygen Reduction Reaction(ORR)

The electrochemical step in which oxygen gains electrons at an electrode, the reaction that generates electricity in a fuel cell or solid oxide cell.

Oxytocin

A hormone and neurotransmitter, sometimes called the 'bonding hormone,' that rises during trust-building social contact such as physical touch, cooperation and close relationships, and is increasingly studied for its role in signaling vigilance as well as connection during social interactions.

Paleoclimate Proxy

A natural archive such as coral, ice or sediment whose physical or chemical properties are used to estimate past climate conditions.

Paleolake

A lake that existed in the geological past but has since dried up or disappeared. Scientists identify paleolakes from landforms, sediments and minerals that record former shorelines, water depths and changes in climate.

Pancreatic Ductal Adenocarcinoma(PDAC)

The most common form of pancreatic cancer, arising from cells that line the pancreatic ducts. It is often diagnosed after it has spread and is biologically distinct from pancreatic neuroendocrine tumours.

Paraspeckle

A membraneless structure inside the cell nucleus that organizes specific RNA molecules and proteins.

Parental Controls

Settings that allow a parent or guardian to restrict, monitor or approve aspects of a child’s use of a device or digital service, including time, content, messaging and purchases.

Passive State Indicator

A visual or physical indicator that communicates the current state of an object without electrical power, often by coupling its display directly to a mechanical position, temperature or material change.

Path of Totality

The narrow track on Earth's surface, typically 100 to 200 kilometers wide, that the Moon's umbra crosses during a total solar eclipse. Only observers inside this path see full darkness.

Payload Deployment

The controlled release of a satellite, probe or other cargo from its launch vehicle after the required flight conditions are reached. Deployment mechanisms must separate the payload without collision, impart excessive rotation or contaminate sensitive surfaces, while leaving it in a trajectory from which it can begin operations.

Payload Fairing

A protective shell around satellites or other payloads at the top of a launch vehicle. It shields them from airflow, heating and contamination during ascent, then separates after the atmosphere becomes thin enough.

PCSK9 Inhibitor

A medicine that blocks the activity of the PCSK9 protein, allowing the liver to remove more LDL cholesterol from the blood. Available approaches include antibodies and gene-silencing drugs; they are generally used for selected patients alongside lifestyle changes and other lipid-lowering treatment.

Peak Warming

The highest level of long-term global temperature increase reached before warming stabilizes or begins to decline. It depends on cumulative greenhouse-gas emissions and how quickly the world reaches net zero.

Peer List Poisoning

The deliberate insertion of false or defender-controlled entries into the list of peers a decentralized application trusts, redirecting or isolating its communications.