FD

FD or similar may refer to:

Science and technology

 * Canon FD lens mount, a standard for connecting a lens to a camera
 * Familial dysautonomia, a disorder of the autonomic nervous system
 * Fermi–Dirac statistics (F–D statistics), in quantum statistics
 * Ferredoxin, iron–sulfur proteins
 * File descriptor, in Unix and related computer operating systems
 * Freedesktop.org (fd.o), an interoperability project
 * Functional dependency, a constraint in a relation from a database
 * Nissan FD engine, for trucks and buses

Transportation

 * Thai AirAsia, IATA airline code FD
 * Mazda RX-7 (FD), a car
 * FD Phantom, original name for the FH Phantom jet fighter
 * Russian locomotive class FD
 * Flight director (aeronautics), a flight instrument
 * Flying Dutchman (dinghy)

Other uses

 * Fidei defensor (Latin, 'Defender of the Faith'), part of the full style of many English/British monarchs
 * Fixed deposit, a financial instrument
 * Finance Director, or chief financial officer, in a company
 * Fire Department, providing firefighting services
 * Force of the Right (Forța Dreptei), a Romanian political party