Foil

Foil may refer to:

Materials

• Foil (metal), a quite thin sheet of metal, usually manufactured with a rolling mill machine
• Metal leaf, a very thin sheet of decorative metal
• Aluminium foil, a type of wrapping for food
• Tin foil, metal foil made of tin, the direct predecessor to aluminium foil
• Plastic foil, a thin layer of plastic material
  • Transparency (projection), as in "foil" (film over incandescent light) or "viewfoil"

Fluid dynamics

• Foil (fluid mechanics)
  • Airfoil, a foil operating in air
  • Hydrofoil, a foil operating in water
  • Parafoil, a non-rigid airfoil, inflated during use
• Foil bearing, a type of fluid bearing

Arts and culture

• Foil stamping, a printmaking technique
• Foil (band), a Seattle-based grunge rock band c.1990 - 98
• Foil (literature), a subsidiary character who emphasizes the traits of a main character
  • A Comedic (or comic) foil, is the straight man in a comedy double act

Mathematics

• The FOIL method, a way to expand the product of two first-degree polynomials ("linear factors")

Navigation

• Hydrofoil, a type of high-powered motorboat that uses underwater foils to lift its hull above the water when moving at high speeds
• Bruce foil, a foil used on an outrigger to prevent a boat from heeling
• Centerboard, a movable keel that functions as a foil
• Foilboard, a surfboard using a hydrofoil

Other

• People in a police lineup
• First Order Inductive Learner - a rule-based learning algorithm
• FOIL (programming language), one of two now-defunct computer programming languages
• Foil (fencing), one of the three weapons used in modern fencing
• Forum of Indian Leftists, a political group of Indian intellectuals
• Freedom of information legislation or Freedom of Information Law (FOIL)
• Ultrasonic foil (papermaking), a type of high frequency vibrating foil involved in papermaking