Cross section (geometry)

PN may refer to:

• p-n junction, a type of junction in electronics
• Pitcairn Islands, ISO 3166-1 country code
  • .pn, the country code top level domain (ccTLD) for Pitcairn Islands
• Pacific National, a rail freight company in Australia
• Palmerston North, a city in New Zealand
• Parenteral nutrition
• Part number
• Participatory notes
• Pascal Nouma, a former player of Beşiktaş J.K.
• Pat Nixon, a former First Lady of the United States
• Path graph of size $n$, denoted by $P_n$
• Patriotic Nigras, a powerful griefing group in Second Life
• Pennsylvania Northeastern Railroad, reporting mark
• Petri Net
• Phylogenetic nomenclature, an approach to naming groups of living things
• Polynomial vector spaces, which may be denoted by ${\mathbb{\mathbb{P}}}_n$
• Post-Newtonian expansion, an approximation of General Relativity
• Pottery Neolithic (see Neolithic)
• Programmer's Notepad, a text editor
• Promissory note, a contract where one party makes an unconditional promise in writing to pay a sum of money to another
• Proper noun, a linguistic term for the name of an entity
• Proportional navigation, a concept in missile guidance systems
• Pseudorandom number sequence
• pseudonoise aka pseudorandom noise, a deterministic sequence of pulses used in spread spectrum communication and rangefinding
• Purple Noon, a 1960 film

Political Parties

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

Navies

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