FI or fi may refer to:

In arts and entertainment

Businesses and organizations


In technology

  • fi, a scripting command in the Bourne shell and its derivatives
  • Forced induction, the process of delivering compressed air to the intake of an internal combustion engine
  • Fuel injection, a system for introducing fuel into internal combustion engines
  • Fast Infoset, a standard for binary XML Infoset encoding

Other uses

  • Phi (Φ), a letter of the Greek alphabet