DragonFable, a single-player RPG that runs on a browser

DF, a Gangsta rapper from Winnende in Germany

DeFRaG, an unofficial Quake III Arena modification

Danish People's Party (Dansk Folkeparti)

Density function, a mathematical function which has a wide range of applications such as in the study of macromolecular structure

Star Wars: Dark Forces, a 1995 first-person shooter by LucasArts

Direction finding, a technique used to locate a radio transmitter

DragonForce, a British power metal band

df (Unix), a Unix command to report disk space usage by filesystem

Dark Future, a 1988 miniature wargame by Games Workshop

Slaves to Armok II: Dwarf Fortress, a 2006 computer game by Bay 12 Games

District Fellows, the 16-20 age group of the Woodcraft Folk

Dungeon Family, an Atlanta hip hop music collective

Dean Foods

Dongfeng, see Dongfeng (disambiguation)

Degrees of freedom, a measure of the number of independent pieces of information on which a parameter estimate is based

Distrito Federal, e.g. the Mexican Federal District or Brazilian Federal District

Despair Faction, a fan club for the band AFI

Methylphosphonyl difluoride, a chemical weapons precursor listed in schedule 1 of the Chemical Weapons Convention

DF is the chemical formula for deuterium fluoride: see for example deuterium fluoride laser