FD

FD can stand for:

Science & Technology

• Canon FD lens mount
• Fermi–Dirac statistics
• Ferredoxin, a molecule functioning in electron transfer
• File descriptor, a component in the Unix operating system
• Finite difference, a mathematical expression
• Floppy disk, an obsolete data storage device
• USB Flash drive, a data storage device which has replaced the floppy disk
• Full-duplex, the description for a two way communication system
• Functional dependency, a constraint in a relation from a database
• Full disclosure
• FreeDOS, an open-source DOS-compatible operating system

Transport

• Thai AirAsia's IATA code
• Mazda RX-7's model designation
• FH Phantom or FD Phantom, a jet fighter
• Steam locomotive FD, a Soviet steam locomotive
• Flight director (aviation)
• Flying Dutchman (dinghy)

Medical

• F & D, fixed and dilated
• Familial dysautonomia or Riley-Day syndrome), a nervous system disorder
• Fabry disease
• fetal demise
• fetal distress
• focal distance
• forceps delivery
• free drain
• full denture
• fully dilated
• functional deficits
• Forestier Disease
• food diary

Other uses

• Felony disenfranchisement, restricting former felons from voting in an election
• Fidei defensor
• Fire department
• Fortified District, a defensive fortified organization of the Imperial Japanese Army (World War II)
• Foundation Degree, a vocational qualification in the United Kingdom
• Free dance (figure skating), usually the third part of an ice dancing competition
• Funeral director, a professional involved in the business of funeral rites
• St. John's Fog Devils, the name for a former Quebec Major Junior Hockey League team based in St. John's in Newfoundland and Labrador, Canada