Companies and organizations

• Academic Programs International, an American study-abroad provider
• American Petroleum Institute, an American trade-lobbying and international-standardization organization
• AmeriStat Pharmaceuticals, Inc., a US-based international wholesaler and exporter of pharmaceuticals and medical supplies
• Animal Protection Institute, an American non-profit organization
• Anonima Petroli Italiana, an Italian petrol (gasoline) company
• Associated Producers Incorporated a B picture subsidiary of 20th Century Fox
• Athletes' Performance Institute, an American training facility for competitive athletes
• Australian Pharmaceutical Industries
• Australian Property Institute, an Australian professional organization in valuation
• Automated Processes, Inc., an American audio electronics company
• Automobile Products of India, an Indian automotive company
• Aviation Partners Inc., an American aviation components company

In education

• Academic Performance Index, a measure of scholastic performance used in California, United States
• Auburn University, formerly known as Alabama Polytechnic Institute

Places

• Api (mountain), Nepal
• Api Chamber, a large cave chamber in Malaysia
• Mount Api, Malaysia

In politics

• Alliance for Italy, a centrist political party in Italy
• Arab Peace Initiative, a peace initiative proposed in 2002 at the Beirut Summit of the Arab League

In science and technology

• Active pharmaceutical ingredient, a basic component of any medicine or pharmaceutical drug
• Advanced primer ignition, a type of blowback operation for firearms that ignites the primer when the bolt is still moving with the goal of increasing rate of fire and decreasing felt recoil.
• Petroleum industry nomenclature deriving from American Petroleum Institute
  • API gravity, a measure of the density of petroleum
  • API number, a unique identifier applied to each petroleum exploration or production well drilled in the United States
  • API unit, a standard measure of natural gamma radiation measured in a borehole
• Analytical Profile Index, a miniaturized panel of biochemical tests compiled for identification of groups of closely related bacteria
• API oil-water separator
• Air Pollution Index, a measure of air quality used in Hong Kong and Malaysia
• Armor-piercing incendiary, a type of armor-piercing shot and shell
• Atmospheric pressure ionization, a type of ionization in mass spectrometry
• Apnea–hypopnea index, an index used to indicate the severity of sleep apnea

Other uses

• Advance passenger information, passenger name record collected by commercial transportation operations
• Asian-Pacific Islander
• Aviation Preflight Indoctrination, the first major phase of training for a United States Naval Aviator
• Announcement in the public interest, an alternate name for a public-service announcement
• International Phonetic Alphabet, a system of phonetic notation (known in French as the alphabet phonétique international)
• Api (apple), an apple cultivar.

See also

• AP1 (disambiguation)
• API Network, an Australian organisation of public intellectuals, and book publisher