People

• King Pap of Armenia
• Arthur Pap, philosopher
• The nickname of Mike Papantonio, a Florida-based trial attorney and co-host of Ring of Fire on Air America Radio
• Pap Finn, Huck's father in the novel The Adventures of Huckleberry Finn by Mark Twain
• Jonathan Papelbon, closing pitcher for the Boston Red Sox.

Places

• Pap, a village in northeastern Hungary
• PAP, the IATA airport code for Port-au-Prince International Airport
• Port-au-Prince, capital city of Haiti
• Pap (city), a city in Uzbekistan

Organizations

• Pan-African Parliament, legislative body of the African Union
• Partido Aprista Peruano, political party in Peru
• People's Action Party, political party in Singapore
• People's Armed Police, police force in the People's Republic of China
• Polska Agencja Prasowa, news agency in Poland
• Poverty Alleviating Party, political party in Maldives
• Promociones Antonio Peña, professional wrestling promotion based in Mexico
• Provincial Assembly of the Punjab, house of elected representatives in Pakistan

Technology

• Password authentication protocol, for identifying computer users to a remote server
• Picture and Picture, two image sources displayed side by side on a television screen
• Plastic Animation Paper, 2D animation software
• Plug-and-play, automated computer hardware configuration
• Push Access Protocol, part of the Wireless Application Protocol suite
• PEX-AL-PEX, a special type of Cross-linked polyethylene (PEX) pipe with the additional layer of aluminum

Biology and medicine

• Polyadenylate polymerase, enzyme involved in creation of mRNA tails
• Positive airway pressure, method of respiratory ventilation used primarily in the treatment of sleep apnea
• Prostatic acid phosphatase
• Pulmonary Arterial Pressure
• Purple acid phosphatases
• Phosphatidic acid phosphatase

Other

• Pablum, cereal for infants
• pap, the ISO 639 individual language code for the Caribbean language of Papiamento or Papiamentu
• Pap (food), type of South African food
• Pap smear, method for detecting abnormalities in the cells of a woman's cervix
• Slang for paparazzi.
• Personal auto policy, a vehicle insurance term
• PAP, Principle of Alternate Possibilities, Philosophy of the Mind
• Primes in arithmetic progression, prime numbers with the same difference
• Project Affected People (World Bank term)