1. See also

4F or 4-F may refer to:

• 4F, or four flats, key signature of A-flat major in music
• 4F (company), a Polish sportswear company
• 4-F classification in the U.S. Selective Service System, identifying a person as unfit for military service
• 4F correlator, in Fourier optics
• Flottille 4F a French naval aviation squadron
• LMS Fowler Class 4F, a class of 0-6-0 steam locomotive
• 4F, the production code for the 1975 Doctor Who serial Terror of the Zygons

See also

• F4 (disambiguation)
• Four Fs (disambiguation)

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