Computing
- Application software
- Mobile app, software designed to run on smartphones and other mobile devices
- Web application or web app, software designed to run inside a web browser
- Adjusted Peak Performance, a metric to measure computing performance in 64-bit processors and above
- Application Portability Profile, NIST standards and specifications for the Open System Environment
- Atom Publishing Protocol, simple HTTP-based protocol for creating and updating web resources
People
Arts, entertainment and media
- APP (film), a 2013 Dutch film that utilizes second screen technology
- Asbury Park Press, a newspaper of Monmouth County, New Jersey, US
Education
- Advanced Placement Program, a program offering college-level curriculum and examinations to high school students
- Appalachian State University, a university in Boone, North Carolina, US
- Appalachian State Mountaineers, the university’s athletic program
- Assessing Pupils’ Progress, an assessment methodology used in schools in England and Wales
Medicine
- Acute-phase protein, a class of proteins whose concentration changes in response to inflammation
- Advanced practice provider, or mid-level practitioner, a class of healthcare providers
- Amyloid precursor protein, a protein whose fragments are associated with Alzheimer’s disease and other neurological disorders
Organizations
- African Prisons Project, a UK-based NGO
- Alberta Provincial Police, a Canadian police force from 1917 to 1932
- American Principles Project, a libertarian and conservative political think tank
- Asia-Pacific Partnership, an international environmental protection alliance
- Asia Pulp & Paper, a pulp and paper company based in Jakarta, Indonesia
- Associated Press of Pakistan, a national news agency of Pakistan
- Association of Professional Piercers, an international organization for body piercing
Politics
- All People’s Party (disambiguation)
- Alliance populaire progressiste or People’s Progressive Alliance, a political party in Mauritania
- Animal Protection Party, a British political party
- Australian Protectionist Party, an Australian political party
- Austrian People’s Party, an Austrian political party
- Reason Party (Poland) or Anticlerical Progress Party REASON, a Polish political party
- Aggrupation of Parties for Progress, a Philippine local political party
Railways
- Appleby railway station (National Rail code), England
- Appleton, Wisconsin (Amtrak station code)
Other uses
- Atactic polypropylene, a hot-melt adhesive
- Authorized push payment fraud (APP fraud), fraudulent diversion of funds
