Mick Foley, retired professional wrestler.

Myelofibrosis, a chronic clonal malignant disease

MF (thousand feet), an information technology (IT) term for cable length (from the roman numeral M for thousand and F for feet)

Power Rangers: Mystic Force.

Mylène Farmer, a Canadian-born French singer and songwriter.

Motherfucker, an insult

Mezzo-forte, a musical dynamic range (Italian for "medium-strong")

Mitsubishi Fuso Truck and Bus Corporation, a Japanese manufacturer of trucks and buses

MF Norwegian School of Theology, Det teologiske Menighetsfakultet in Norwegian

Xiamen Airlines IATA airline designator

METAFONT, a programming language for defining vector fonts using powerful geometrical equations.

Medium frequency, radio transmissions between the frequencies of 300 kHz and 3000 kHz

modeFRONTIER, a multi-objective optimization and design environment software

Mandatory frequency for traffic advisories at an airport.

M/F, a novel by Anthony Burgess

Mainframe, in computing

Maynard Ferguson, a former world-class trumpeter

Manual focus, a feature of an optical system that allows the user to obtain and maintain correct focus on a target manually. (see also AF)

Saint Martin: ISO 3166-1 alpha-2 country code

Mayotte: FIPS PUB 10-4 territory code

Megafarad, an SI unit of electric capacitance

Melodifestivalen, the Swedish preselection for the Eurovision Song Contest

"Metal Face" Doom (Daniel Dumile), an American hip-hop artist

"Mad Flows" Grimm, a hip-hop artist

Midfield, a playing position in association football (soccer)

Monster Force, a 1994 animated television series

Mossy fiber, in neuroscience

Multi-frequency, in telephony

Mutual Fund, in investing

Prefix for steel rolling stock on Paris Métro (eg MF 67, MF 77, MF 88 and MF 2000)

millifarad, an SI unit of electric capacitance