All articles starting with P

Principle of locality

The principle of locality, also known as the locality principle, states that an event can be influenced only by its immediate surroundings, with no influence propagating faster than light.

Principle of maximum entropy

The principle of maximum entropy, also known as MaxEnt, holds that the least biased probability distribution is the one with the largest entropy that satisfies the known constraints.

Principle of relativity

The principle of relativity states that the laws of physics take the same form in every inertial frame, so no experiment can reveal uniform motion.

Principle of sufficient reason

Principle of sufficient reason (PSR), coined by Leibniz as principe de raison suffisante, holds every fact has a reason, cause, or ground; central to cosmological arguments, contested via Humean, quantum, and skepticism objections.

Principle of virtual work

The principle of virtual work states that a mechanical system is in equilibrium only when the total work of applied forces vanishes for every virtual displacement.

Principles of European Contract Law

The Principles of European Contract Law (PECL) are proposed general rules for European contract law, drafted by the Ole Lando-chaired Commission and published between 2000 and 2003.

Principles of Geology

Principles of Geology is a three-volume work by Scottish geologist Charles Lyell, published between 1830 and 1833, arguing that present-day processes shaped Earth's past and heavily influencing Darwin.

Principles of grouping

Principles of grouping, or Gestalt laws, are rules of visual perceptual organization, including proximity, similarity, closure, good continuation, common fate, and Prägnanz, formulated by Wertheimer in 1923 and later quantified and given neural and computational accounts.

Principles of learning

Principles of learning: empirically established regularities of human learning. Rooted in behaviorism, cognitivism, and constructivism; best-evidenced strategies are spacing, retrieval practice (testing effect, g = 0.50 in classrooms), and interleaving, while learning-styles matching lacks support.

Pringles

Pringles: American stackable saddle-shaped potato crisps in a tubular can, launched by Procter & Gamble in 1968. Inventors Baur, Liepa, Wolfe. Owned by Kellogg 2012, Kellanova, then Mars since December 2025. Over 160 flavors, sold in 140+ countries.

Prinia

Prinia is a genus of small, long-tailed cisticolid warblers (23–28 species) resident across Africa and southern Asia to western Indonesia, including the Plain, Ashy, Graceful, and Karoo Prinias, recently reshaped by DNA-based species splits.

Oct 20, 2026

Prinomastat

Prinomastat (AG3340), an Agouron/Pfizer nonpeptidic hydroxamate MMP-2/-9/-13/-14 inhibitor and angiogenesis inhibitor, reached phase III trials in lung and prostate cancer but showed no survival benefit and was discontinued.

Oct 20, 2026

Prins Karls Forland

Prins Karls Forland, Svalbard's westernmost island off Spitsbergen, 85 km long, highest peak Monacofjellet 1084 m; Forlandet National Park (1973), northernmost harbor seals and Brünnich's guillemot colony, named after King Charles I.

Sep 19, 2026

Prins Thomas

Prins Thomas, born Thomas Moen Hermansen in 1975, is a Norwegian DJ and record producer from Oslo associated with space disco, who has run the Full Pupp label since 2005.

Print on demand

Print on demand (POD) is a digital printing model where a book is printed only after a sale, from a stored PDF, with no warehouse stock. Key traits: higher per-unit cost than offset, backlist and self-publishing uses, KDP and IngramSpark platforms.

Printed circuit board

A printed circuit board, or PCB, is an insulating board with etched copper traces that both connects electronic components and supports them mechanically, underpinning nearly all electronics.

Printed circuit board manufacturing

Printed circuit board manufacturing is the industrial process that turns circuit design data into a bare board with patterned copper, plated holes, and solder mask.

Printer (computing)

A printer, or computer printer, is a peripheral device that produces a permanent copy of text or graphics, usually on paper, from data sent by a computer.

Printing

Printing reproduces text and images in multiple copies by transferring ink from a block, type, or plate onto paper, dating from East Asian woodblock printing.

Printing and distribution of the Guru Granth Sahib

Printing and distribution of the Guru Granth Sahib, Sikhism's principal scripture, is controlled by the SGPC, whose 1951 edition fixed the text at 1,430 pages.

Printing press

A printing press is a machine that presses an inked surface of movable type or a plate against paper to make many copies of the same image.

Printmaking

Printmaking is the art of transferring an image from a matrix, such as a woodblock, metal plate, or stone, to paper in repeatable impressions. Main categories are relief, intaglio, planographic, and stencil processes, from woodcut to screenprint.

Sep 19, 2026

Printworks London

Printworks London was an electronic music and cultural venue in Surrey Quays, south-east London, housed in a former newspaper printing hall and run by Broadwick Live from 2017 to 2023.

Oct 10, 2026

Prio

PRIO is a Portuguese energy company owned by the DISA group with over 250 stations. The name is often confused with the former Shell network in Norway.

Prion

Prion (proteinaceous infectious particle): infectious agent of misfolded PrPSc protein without nucleic acid, causing fatal diseases such as CJD, BSE, scrapie, and CWD; replicates by templating PrPC conversion; no treatment exists.

Prioniodina

Prioniodina (Bassler, 1925) is an extinct conodont genus in the family Prioniodinidae, order Prioniodinida, with type species P. subcurvata; its curved, denticulated ramiform elements range from the Ordovician to the Triassic.

Prior art

Prior art: the body of public knowledge (patents, printed publications, public uses, and sales) existing before a filing date, used to judge patent novelty and inventive step under US, EPO, and PCT law.

Prior Authorization

Prior authorization (preauthorization, precertification): health plan approval required before a service, drug, or equipment is covered. Used across Medicare Advantage, Medicaid, and commercial plans; CMS-0057-F sets 72-hour/7-day decision deadlines.

Prior probability

A prior probability distribution, or prior, is the probability distribution assigned to a statistical model's parameters before the current data are observed, combined with the likelihood in Bayesian analysis to form the posterior distribution.