From Longman Dictionary of Contemporary Englishfoilfoil1 /fɔɪl/ ●○○ noun 1 
[uncountable]DF metal sheets that are as thin as paper, used for wrapping foodsilver/aluminium/kitchen foil Cover the chicken with silver foil and bake. → tinfoil2 [uncountable]DF paper that is covered with very thin sheets of metal chocolates in foil wrappers3 → be a foil to/for somebody/something4 [countable]DSO a light narrow sword used in fencing
[uncountable]DF metal sheets that are as thin as paper, used for wrapping foodsilver/aluminium/kitchen foil Cover the chicken with silver foil and bake. → tinfoil2 [uncountable]DF paper that is covered with very thin sheets of metal chocolates in foil wrappers3 → be a foil to/for somebody/something4 [countable]DSO a light narrow sword used in fencingExamples from the Corpus
foil• Fashion has often been a foil to the seriousness of art.• They could conveniently make a foil out of all the churches, because so many conservatives in churches opposed suffrage.• The new clothes became a clever foil for his old self.• The hardier hot foil printing burns the foil on to the leather so that it doesn't rub off.• Wrap in foil and bake in a 350 F oven until garlic is very soft and sweet, about 1 hour.• Then reduce oven setting to 200°C, 400°F, Gas Mark 6 and open the foil so that the bread browns and crisps.• A useful foil for bright flowers.• Cover the turkey with foil and bake in a hot oven.silver/aluminium/kitchen foil• To increase the amount of light, line the box with aluminium kitchen foil.• Small moulds for casting blocks can be made from aluminium foil.• A final covering of aluminium foil or carbon paper reduces the risk of detection by X-ray machines.• Take 4 large pieces of aluminium foil and place a quarter of the potatoes, onions and apples on each.• A tube of silver foil folded over a loop of line pulled down about eighteen inches between bite alarm and reel.• Don't use ordinary kitchen foil unless you are willing to replace it seasonally, since it tends to tarnish.• I love the shiny brown line, I love the crinkle of the silver foil.• Weight the bird; transfer to a rack in a roasting tin and cover with aluminium foil.foilfoil2 verb [transitive] PREVENTto prevent something bad that someone is planning to do A massive arms-smuggling plan has been foiled by the CIA.Grammar Foil is often used in the passive.→ See Verb tableExamples from the Corpus
foil• For the male, it is a stiff competition, but even the strongest can be unwittingly foiled.• Read in studio An eighty four year old man has foiled a mugger who tried to steal his pension book.• The government has foiled an attempted military coup.• The burglar was foiled by a passer-by who noticed the broken window and phoned the police.• An ambition to become a pilot was foiled by an eye-sight deficiency.• The escape attempt was foiled by police guards.• Or, to put it another way, genes that foil meiotic drivers will spread as surely as meiotic drivers will spread.• But troops loyal to the general foiled the attempt and he emerged with his customary grin and triumphal air-punching.• He said this could foil the widely held expectation that cable and telephone companies will become chief competitors.• Their first attempt, however, was foiled when they lost the centre leaf and had to walk out at this point.Origin foil1 (1300-1400) Old French Latin folium “leaf” foil2 (1300-1400) French fouler “to step on” 