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Perplexity–Cloudflare scraping dispute
The Perplexity–Cloudflare scraping dispute is a 2025 conflict in which Cloudflare accused Perplexity of stealth crawlers disguised as browser traffic to evade robots.txt, which Perplexity denied while Japanese publishers sued.
Perry McCarty
Perry Lee McCarty (1931–2023) was an American environmental engineer and longtime Stanford professor, a founder of environmental engineering who pioneered environmental biotechnology and won the 2007 Stockholm Water Prize.
Perry nuclear power plant
The Perry nuclear power plant is a single-unit boiling water reactor power station in Perry, Ohio, on Lake Erie northeast of Cleveland, operating since 1986.
Persephone Oil and Gas Field
The Persephone field is a gas-condensate field on Australia's North West Shelf off Western Australia, discovered in 2006 and operated by Woodside Energy through the North Rankin platforms.
Perseus Oil and Gas Field
The Perseus field is a giant gas and condensate field on Australia's North West Shelf, about 135 km offshore from Karratha, Western Australia, producing into the NWS Project since 1991.
Perseverance (rover)
Perseverance, a car-sized NASA rover nicknamed Percy, landed in Mars' Jezero Crater in February 2021 to seek signs of ancient microbial life and cache rock samples for return to Earth.
Pershing II
The Pershing II (MGM-31B) was a two-stage, road-mobile American medium-range ballistic missile deployed in West Germany from 1983 until its elimination under the 1987 INF Treaty.
Pershing locomotive
The Pershing locomotive, or Pershing class, was a 2-8-0 steam locomotive built by Baldwin from 1917 to 1919 for American forces in France during World War I.
Persian architecture
Persian architecture is the building tradition of the Iranian plateau, spanning roughly three millennia from the Achaemenid Empire through the Parthian, Sasanian, and Islamic periods to today.
Persian Gulf submarine telegraph cables
The Persian Gulf submarine telegraph cables were undersea telegraph lines laid from 1864 across the Gulf, first supervised by Sir Charles Tilston Bright, carrying Britain-to-India messages in days instead of months.
Persil
Persil, sold as Dixan in some markets, is a laundry detergent brand launched in 1907 by Henkel, described as the world's first self-acting detergent; Unilever sells Persil in the United Kingdom.
Persistent data structure
A persistent data structure preserves every previous version of itself when updated, letting all versions be accessed; techniques include fat nodes, path copying, and structural sharing.
Persistent homology
Persistent homology is a topological data analysis method that tracks features like connected components, loops, and voids across scales, summarizing them as a barcode; long-lived features count as signal, short-lived ones as noise.
Persistent monitoring and surveillance
Persistent monitoring is a robotics problem where mobile robots repeatedly visit every part of an environment to keep information about it continuously up to date.
Persistent Systems
Persistent Systems is an Indian IT services and consulting company founded in 1990 and operating in 15 countries, known for digital engineering, enterprise modernization, and cloud services.
Person re-identification
Person re-identification (re-ID) is a computer vision task that assigns the same identity to a person seen in images or videos from different cameras, supporting multi-camera surveillance.
Persona (identity verification service)
Persona, formally Persona Identities, is an American identity verification company in San Francisco founded in 2018 by Rick Song and Charles Yeh, valued at $2 billion in 2025.
Persona (user experience)
A persona, in user experience design, is a fictional but realistic description of a typical product user, built from research to help design teams make decisions.
Personal computer
A personal computer (PC) is a computer designed for use by one individual at a time, covering desktops, laptops, and tablets but excluding smartphones; the IBM PC of 1981 set the standard most still follow.
Personal data
Personal data, also called personally identifiable information (PII), is any information relating to an identified or identifiable person, such as a name, address, or IP address.
Personal defense weapon
A personal defense weapon (PDW) is a compact firearm for troops not on the front lines, firing a small high-velocity cartridge that defeats body armor.
Personal digital assistant
A personal digital assistant, or PDA, is a handheld computer for email and personal organization, a category named by Apple's John Sculley in 1992 that later merged with telephony into the smartphone.
Personal Digital Cellular
Personal Digital Cellular (PDC), also called Japanese Digital Cellular, was a 2G mobile phone standard used exclusively in Japan from 1993, peaking at nearly 80 million subscribers.
Personal Handy-phone System
The Personal Handy-phone System (PHS) is a Japanese digital wireless standard, launched in 1995, whose handsets worked as cordless phones indoors and low-cost mobile phones outdoors.
Personal Information Protection Act (South Korea)
The Personal Information Protection Act (개인정보 보호법, PIPA) is South Korea's comprehensive data protection law, enacted in 2011 to govern personal information processing by public institutions and private companies.
Personal Information Protection and Electronic Documents Act
The Personal Information Protection and Electronic Documents Act, known as PIPEDA, is Canada's federal private-sector privacy law, enacted in 2000 and administered by the Office of the Privacy Commissioner.
Personal Information Protection Law (China)
The Personal Information Protection Law (中华人民共和国个人信息保护法, PIPL) is China's first comprehensive data privacy law, adopted in August 2021 and effective 1 November 2021, regulating how personal information is collected and used.
Personal lubricant
A personal lubricant, also called a sexual lubricant or sex lube, is a water-, silicone-, or oil-based product that reduces friction during sexual activity and supplements natural lubrication.
Personal RF safety monitor
A personal RF safety monitor is a small body-worn device that measures radiofrequency electromagnetic fields and warns the wearer with light, sound, and vibration when exposure limits are approached.
Personal thermal management
Personal thermal management is the set of technologies that keep an individual comfortable by conditioning the microclimate around the body rather than the whole building.