noun
Thin sheet of aluminum used for cooking, wrapping, or insulation.
アルミ箔でじゃがいもを包んでオーブンで焼いた。
I wrapped the potatoes in aluminum foil and baked them in the oven.
ホイル is a more general term for foil, often used in compounds like アルミホイル (aluminum foil) or キッチンホイル (kitchen foil). アルミ箔 specifically refers to aluminum foil.
Compound of アルミ (from English 'aluminum') and 箔 (foil, leaf).