FINS, Factory Interface Network Service, is a network protocol used by Omron PLCs, over different physical networks like Ethernet, Controller Link, DeviceNet and RS-232C.

FIN may refer to:

• Finland (ISO 3166-1 alpha-3-code: FIN), a Nordic country in Europe
• ICAO code for Finnair
• FASB Interpretation Number, an identifier for documents published by the Financial Accounting Standards Board
• Federazione Italiana Nuoto, the Italian Swimming Federation
• A FIN packet in the Transmission Control Protocol (TCP)
• Internationalist League of Norway (Norwegian: Forbundet Internasjonalen i Noreg)
• Force Identification Number, a four-character code used to identify uniformed police officers
• fin (band) British indie rock band. Name is spelt fiN (with a capital N)

A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluid media. Fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation.

Fin (not to be confused with British rock band Fin) were a British alternative rock band formed in 1993, who achieved mild success on the independent circuit in the UK.