MID or Mid may refer to: Computers and electronics MapInfo Interchange Format; .mid is also sometimes used as the filename extension for some MapInfo files Media Identification Code (MID code), a code indicating the manufacturer of a DVD Mobile Internet device, a category of mobile computer Molded interconnect device, an injection molded thermoplastic part with integrated electronic circuit traces Multiple interface declaration, a construct in some computer programming languages Musical Instrument Digital Interface, .mid is sometimes used as an alternate filename extension for MIDI files Medicine and biology Multi-infarct dementia, a disease also known as vascular dementia Minimal important difference, the smallest improvement felt to be meaningful by a patient Monocyte, a type of white blood cell in the innate immune system of vertebrates Military Maritime identification digits, a 3-digit code identifying the country of a ship/coastal station using communication equipment. Mentioned in dispatches, a military award for gallantry or otherwise commendable service Militarized interstate dispute, conflicts between states that do not involve full-scale wars Military Intelligence Division (United States), a former military intelligence branch of the United States Army Other Integration and Development Movement, a political party in Argentina Mérida International Airport (IATA: MID) Middletown station (Pennsylvania) (Amtrak station code: MID) Modesto Irrigation District, a special district in California Mortgage interest deduction, a tax deduction for mortgage interest paid by homeowners Measuring Instruments Directive Mid vowel Midfielder, a position in association football Ministry of Foreign Affairs (Russia), for which MID is a colloquial term See also MIDS (disambiguation)