A fir is a type of evergreen coniferous tree.

Fir, FIR or F.I.R. may also refer to:

Entertainment

• F.I.R., a Taiwanese pop music group

• F.I.R. (album)

• F. I. R. (1999 film), an Indian Malayalam-language action film

• F.I.R No. 339/07/06, a 2021 Indian Bengali-language crime thriller film

• FIR (2022 film), an Indian Tamil-language action thriller film

• F.I.R. (TV series), an Indian sitcom

• Falling in Reverse, an American rock band

Science and technology

• Far infrared

• Finite impulse response, a type of filter in signal processing

• Free ideal ring

• Flight information region

• FiR 1, the first nuclear reactor in Finland

• Research Institute for Operations Management (), in Germany

Other uses

• Fir, an alternative spelling of Fier, a city in Albania

• Firan language (ISO 639-3 language code: )

• First information report, a police document in some countries

• Flats Industrial Railroad, a former US company

• Flight information region, Specified region of airspace

• International Federation of Resistance Fighters – Association of Anti-Fascists ()

• Italian Rugby Federation ()

• USCGC Fir, 2 US Coast Guard ships

See also

• FIRS (disambiguation)

• The Firs (disambiguation)