Adi Shankara, Indian mystic

Adi is sometime as known as the abbreviation of Adidas

After Development Inspection, otherwise known as Quality Assurance

The Adi people

Acting Detective Inspector

Acceptable daily intake, in health and medicine

Attitude Director Indicator, aircraft flight instrument

Approved Driving Instructor, a qualified UK car driver trainer

Analog Devices, Incorporated, a corporation that produces electronic articles and signal processing solutions.

American Democracy Institute, a nonpartisan, nonprofit education and research center

Australian Defence Industries

Alternating Direction Implicit, a finite difference method for solving differential equation

Animal Defenders International, a nonprofit campaigning group

ADI club, the Hungarian youth club

The Adi language

Application and Data Integration, in computing

Adi (title): a Fijian title used by females of chiefly rank

Authorised Deposit-Taking Institution, a corporation authorised under the Australian Commonwealth Banking Act 1959

The Banu Adi clan

Associazione per il Disegno Industriale

Adi (name): Bosnian short for Adnan

"Adi", the nickname of nazi-leader Adolf Hitler, used only by his family and closest relatives

Aircraft Designs Inc., an aircraft design firm in Monterey, California