Technology glossary

Plug-In Hybrid Electric Vehicle(PHEV)

A vehicle with both an internal-combustion engine and an electric motor powered by a battery that can be charged from an external source. It can travel a limited distance on electricity before using the engine, with actual fuel savings depending heavily on charging and driving patterns.

Pneumatic Actuation

The production of mechanical movement using compressed air or another gas. Pressure is directed into cylinders, chambers, or flexible structures to create force and motion, a method common in industrial equipment and soft robotics.

Pneumothorax

A condition in which air collects between the lung and chest wall, potentially causing part or all of the lung to collapse.

PNT Resilience

PNT resilience is the ability to maintain or recover reliable positioning, navigation and timing when a primary source such as GNSS is disrupted, degraded or manipulated. It can involve redundant signals, local clocks, inertial sensors and alternative timing sources.

Polar Jet Stream

A fast, narrow current of air that circles a planet at high latitude and can organize large atmospheric waves.

Political Bias Evaluation

The systematic assessment of whether an AI system's outputs favor, disadvantage, or represent political viewpoints unevenly. Reliable evaluation requires diverse prompts, clearly defined measures, contextual analysis, and care not to confuse factual differences with bias.

Polluted White Dwarf

A white dwarf whose visible atmosphere contains heavy elements that should sink rapidly below the surface. Their presence usually indicates that the star is currently or recently accreting debris from asteroids, moons, or other planetary bodies.

Polygenic Risk

Risk influenced by the combined effects of many genetic variants, each usually contributing a small amount.

Polygonal Atmospheric Wave

A wave embedded in a rotating atmospheric jet whose crests form an approximate multi-sided shape when viewed from above.

Polyhydroxyalkanoate (PHA)

A biodegradable plastic compound naturally produced and stored by bacteria and archaea as an internal energy reserve, now also manufactured industrially as a sustainable alternative to conventional plastic.

Polyiodide Shuttle

The unwanted movement of soluble iodine compounds between battery electrodes. This migration removes active material from the cathode, promotes side reactions and can shorten the life of zinc-iodine and related batteries.

Polymorphic File Infector

Malware that attaches itself to executable files while repeatedly changing its code pattern, making simple signature-based detection and removal more difficult.

Polysomnography(PSG)

A comprehensive sleep study that records several body signals, commonly including brain activity, eye movements, muscle activity, airflow, breathing effort, heart rhythm and blood oxygen. Clinicians use the combined record to diagnose sleep disorders and measure their severity.

Porcine Endogenous Retrovirus(PERV)

Viral genetic sequences embedded in the pig genome that can produce virus particles in some conditions. Gene editing and recipient monitoring aim to reduce their potential risk in pig-to-human transplantation.

Positioning, Navigation and Timing(PNT)

Positioning, Navigation and Timing (PNT) describes the three related capabilities supplied by systems such as GPS: determining where something is, guiding movement, and distributing precise time for synchronizing networks and infrastructure.

Potassium Channel Opener

A drug or compound that increases the probability that specific potassium channels in a cell membrane will open. The resulting potassium movement can reduce electrical excitability in neurons or muscle cells. Effects depend on which channel subtype is targeted, the dose, the tissue reached, and whether the compound also affects other channels.

Powder Metallurgy

Manufacturing methods that shape metal powders and bond their particles into solid components using pressure, heat or both.

Power Conversion Efficiency

The percentage of incoming energy that a device converts into the intended useful output. The figure must be interpreted at the stated boundary, because a receiver’s efficiency does not include losses in generating, transmitting or aiming the energy source.

Power Purchase Agreement(PPA)

A long-term contract in which a buyer agrees to purchase electricity, capacity or associated energy attributes from a producer under defined commercial terms. It can reduce price uncertainty for the buyer and support financing for generation assets.

Pre-Deprivation Due Process

Notice and a meaningful opportunity to respond before the government removes a protected right, status or interest.

Prebiotic Chemistry

The study of chemical reactions and environments that could have produced life's molecular building blocks before living organisms existed. It investigates how simple compounds may form amino acids, nucleotides, membranes, and self-organizing chemical systems under early planetary conditions.

Precautionary Transaction Hold

A temporary delay placed on a transfer while a financial institution performs additional risk checks. It is not the same as permanent seizure or cancellation, and the transaction may proceed once the review is completed under the applicable rules.

Precise Point Positioning(PPP)

Precise Point Positioning (PPP) improves GNSS positioning by using precise satellite orbit and clock corrections rather than relying on a nearby local reference station. With suitable receivers and correction data it can reach decimetre- or centimetre-level accuracy.

Precise Time Synchronization

Precise time synchronization keeps clocks across separate devices and networks aligned to a common time reference. GPS and other GNSS systems are widely used to distribute precise time to telecommunications, power grids, financial systems and scientific instruments.

Preliminary Injunction

A temporary court order issued before a case is finally decided. The applicant normally must show likely success, irreparable harm, favorable equities and that the order serves the public interest.

Premarket Tobacco Product Application(PMTA)

The FDA application pathway in which a manufacturer must provide evidence that marketing a new tobacco product would be appropriate for protecting public health.

Premature Termination Codon(PTC)

A stop signal that appears too early in messenger RNA because of a mutation, often producing a shortened or missing protein.

Prerelease AI Evaluation

A structured test of an AI system conducted before public or commercial release to identify capabilities, vulnerabilities or misuse risks that may require safeguards, restricted access or further development.

Prescription Drug Use-Related Software

Software distributed by or on behalf of a drug sponsor that presents an end-user output supplementing, explaining or otherwise relating to one or more of the sponsor’s prescription drugs. Under FDA guidance, the output may be treated as required or promotional drug labeling depending on the software’s role, evidence and connection to a device.

Preserved Thinking

An access-control mechanism that prevents protected reasoning from being edited, replayed, or transferred outside the model or organization that produced it.