Di

Di or DI may refer to:

Arts and media

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), a punk band from Southern California
- D.I. (EP), a 1983 EP by the same band above

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

Di, a prefix used in 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

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

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

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
Direct injection, a type of fuel injection

di (帝), a Chinese word employed in
- the temple names of
  deified Chinese emperors
- Shangdi (Chinese: 上帝, 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) (地), the concept of "earth" in traditional Chinese cosmologies
di, an irregular Latin masculine plural of deus ("god", "deity")

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
Differentiated integration, a mechanism for the European Union's countries to opt out of EU policies