Di or DI may refer to:

Arts and media

Music

* Di, a tone in the solfège ascending chromatic scale existing between Do and Re * dizi (instrument) or di, a Chinese transverse flute * D.I. (band), ''D.I.'' (band), a punk band from Southern California ** D.I. (EP), ''D.I.'' (EP), a 1983 EP by the same band above

Other media

* ''The D.I.'', 1957 military film by Jack Webb * ''Dagens Industri'', a Swedish financial newspaper * DI.FM, an internet radio service

Businesses and organisations

* Defence Intelligence, a UK military intelligence agency * Defensa Interior, an anti-Franco militant anarchist group in 1960s Spain * Deseret Industries, an LDS thrift store * Desert Inn, a former casino in Las Vegas * Direction Italy, a liberal-conservative political party in Italy * Dirgantara Indonesia, an Indonesian aircraft company * Discovery Institute, an intelligent design advocacy group * Norwegian Air UK, a UK based airline (IATA designator) * DynCorp International, a major United States defense contractor

Education

* Diplomi-insinööri, a Finnish 6-year engineering degree * Direct instruction, an instructional method focused on a systematic curriculum design

Natural sciences

* ''Di'', a prefix used in IUPAC nomenclature of organic chemistry, organic chemistry nomenclature * Didymium, a mixture of the elements praseodymium and neodymium once thought to be an element * Diopside, a clinopyroxene mineral * Band 3, a protein * Deionized water, a type of water deprived of the dissolved impurities of ionic nature * ''Diabetes insipidus'', a disease * Iodothyronine deiodinase type I, one of a subfamily of enzymes important in the activation and deactivation of thyroid hormones *Dentinogenesis imperfecta a genetic disorder of tooth development

People

Ethnic groups

* Di (Five Barbarians) (), an ethnic group that overran northern China during the Sixteen Kingdoms period * Beidi or Northern Di (), ethnic groups living in northern China during the Zhou Dynasty

Individuals

* Di (surname) (狄), a Chinese surname sometimes also romanized ''Dee'', particularly: ** Di Renjie a Tang-dynasty official later fictionalized in a series of Chinese detective stories * A diminutive form of the names: ** Diana (given name) ** Diane (disambiguation) ** Dianne (disambiguation) * Diana, Princess of Wales (1961–1997), commonly known as Princess Di or Lady Di

Technology

* Digital intermediate, a filmmaking post-production process * Dependency injection, a method of decoupling components in software * DI unit or Direct Input box, an audio device used with PA systems and in sound recording studios * DI register, or destination index, in x86 computer architecture * Direction indicator, an instrument in aviation also known as a heading indicator * Direct ignition, see Distributor#Direct ignition, Distributor § Direct ignition * Direct injection, a type of fuel injection

Religion

* ''di'' (), a Chinese word employed in ** the temple names of List of rulers of China, deified Chinese emperors ** ''Shangdi'' (Chinese: , lit. "Lord on High"), the Chinese name for the supreme sky god either in native Chinese beliefs or in translation of monotheistic faiths like Christianity and Islam * Di (Chinese concept), ''di'' (Chinese concept) (), the concept of "earth" in traditional Chinese cosmologies * ''di'', an irregular Latin masculine plural of ''deus'' ("god", "deity")

Other uses

* Detective Inspector, a rank in certain police forces * Di (cuneiform), an ancient written sign * Diameter, the distance across the middle of a circle * Di Department, one of the eight departments of the Sourou Province in Burkina Faso * 501 (number) in Roman numerals * Disability insurance, a form of insurance that insures the beneficiary's earned income against the risk that a disability will make working uncomfortable * Hong Kong Document of Identity, issued by the Hong Kong Immigration Department * Drill instructor, a non-commissioned officer in many military or police forces