1Thin sheets of aluminum (foil). Widely used for food wrapping, cooking, insulation, and protection (colloquially called 'aluminum foil').
サンドイッチをアルミ箔で包んで持っていった。
I wrapped the sandwich in aluminum foil and took it with me.
料理の下ごしらえでアルミ箔を敷くと焦げつきを防げる。
Lining with aluminum foil during food prep can prevent burning.