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 technique also used in plays and motion pictures
  • A Comedic (or comic) foil, is the straight man in a comedy double act.
• "Film Over Incandescent Light", a picture-projection method.

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)

Little-known techniques in papermaking

• Foil (papermaking), a type of ving under the wire in the wire section of a paper machine creating a vacuum pulse to eliminate water from the stock (fibre/water slurry).
• Ultrasonic foil (papermaking), a type of high frequency vibrating foil under the wire, creating cavitation, imploding vacuum bubbles, in the stock on the wire. The shock waves from the imploding bubbles will distribute the fibres more uniform in the paper web and this will give a stronger paper