U very light thin sheets of metal used for wrapping things, especially food （尤指包裹食品的）箔，金属薄片
Wrap the cheese in foil to keep it moist. 用锡箔包装奶酪以使其保持松软。
2
C usually singular someone or something that makes another person or thing seem better or more attractive because of the differences between them 陪衬者；陪衬物
+to/for The plain stone floor is a perfect foil to the highly decorated walls. 朴素的石头地面对于装饰精美的墙是绝好的陪衬物。
3
C a light thin sword used in the sport of fencing 花剑；轻剑