Someone who is obese may be called "fat"

File Allocation Table, a file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me.

Fat, a group of compounds that are generally soluble in organic solvents and largely insoluble in water

"Fat", a short story by Raymond Carver from the collection Will You Please Be Quiet, Please?

Someone who is overweight or has excess body fat may be called "fat"

Adipose tissue, an anatomical term for loose connective tissue composed of adipocytes

Fat (Law & Order: Special Victims Unit), an episode of Law & Order: Special Victims Unit

Factory acceptance test or functional acceptance test, in engineering

Fresno Yosemite International Airport; per the International Air Transportation Association (IATA) airport code

Fat Wreck Chords, a punk rock record label

Far Eastern Air Transport, an airline of the Republic of China on Taiwan

Fully Automatic Time, automatic-sensored method of recording race times during running events

Frente Auténtico del Trabajo, a Mexican labor confederation

Fat (novel), a comedy novel by Rob Grant

Forces Armées Tchadiennes, the armed forces of the country of Chad

Fat (song), a song by Weird Al Yankovic from his album Even Worse

Field Artillery Tractor, a military wheeled or tracked vehicle for towing a gun.