n. picture consisting of a positive photograph or drawing on a transparent base; viewed with a projector

n. a light slender flexible sword tipped by a button

n. 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"

n. anything that serves by contrast to call attention to another thing's good qualities; "pretty girls like plain friends as foils"

v. cover or back with foil; "foil mirrors"

v. enhance by contrast; "In this picture, the figures are foiled against the background"