Dictionary definition · foil
noun
- a piece of thin and flexible sheet metal"the photographic film was wrapped in foil"
- anything that serves by contrast to call attention to another thing's good qualities"pretty girls like plain friends as foils"
- a device consisting of a flat or curved piece (as a metal plate) so that its surface reacts to the water it is passing through"the fins of a fish act as hydrofoils"
- picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector
- a light slender flexible sword tipped by a button
verb
- enhance by contrast"In this picture, the figures are foiled against the background"
- hinder or prevent (the efforts, plans, or desires) of"What ultimately frustrated every challenger was Ruth's amazing September surge"
- cover or back with foil"foil mirrors"
Source: Open English WordNet (CC BY 4.0).