- 1 [uncountable] metal made into very thin sheets that is used for covering or wrapping things, especially food aluminum foil Cover the fish loosely with foil and bake for 30 minutes. see also tinfoil
- 2[uncountable] paper that is covered in very thin sheets of metal The chocolates are individually wrapped in gold foil.
- 3[countable] foil (for somebody/something) a person or thing that contrasts with, and therefore emphasizes, the qualities of another person or thing The pale walls provide a perfect foil for the furniture. His mellow guitar technique is the ideal foil for her soaring voice.
- 4[countable] a long, thin, light sword used in the sport of fencing