PN

PN may refer to:

Arts and entertainment

• Purple Noon, a 1960 film
• Patriotic Nigras, a griefing group in the game Second Life

Business and economics

• Pacific National, a rail freight company in Australia
• Participatory notes, issued to unregistered overseas investors in Indian stock markets
• Pennsylvania Northeastern Railroad (reporting mark PN)
• Promissory note, a contract where one party makes an unconditional promise in writing to pay a sum of money to another
• West Air (China) (IATA airline code PN)

Organizations

Navies

• Pakistan Navy
• Peruvian Navy
• Philippine Navy
• Portuguese Navy

Political parties

• National Renaissance Front, Partidul Naţiunii, a political party in Romania
• Partit Nazzjonalista, a political party in Malta

Places

• Pitcairn Islands (ISO 3166-1 country code)
• Palmerston North, a city in New Zealand

Science, technology, and mathematics

Biology

• Parenteral nutrition
• Phylogenetic nomenclature, an approach to naming groups of living thingsfhiml

Electronics and computing

• .pn, the country code top level domain (ccTLD) for Pitcairn Islands
• p-n junction, a type of junction in electronics

Mathematics

• Path graph of size $n$, denoted by $P_{n}$
• Petri net, one of several mathematical modeling languages for the description of distributed systems
• Polish notation, a prefix notation proposed by Jan Łukasiewicz
• Polynomial vector spaces, denoted by $\mathbb {P} _{n}$
• Pseudorandom number sequence

Other uses in science and technology

• Part number, an identifier of a particular part design used in a particular industry
• Particle number, in air-quality measurement
• Planetary nebula, in astronomy
• Post-Newtonian expansion, an approximation of General Relativity
• Proportional navigation, a concept in missile guidance systems
• Pseudorandom noise, a deterministic sequence of pulses used in spread spectrum communication and rangefinding

Other uses

• Pottery Neolithic
• Proper noun, a linguistic term for the name of an entity
• Public News, an alternative newspaper in Houston (1982-1998)