noun
multipurpose knife; Swiss Army knife
Refers to a folding pocketknife with multiple tools, especially the iconic Swiss Army knife. Used in everyday contexts for camping, outdoor activities, or as a handy tool.
キャンプにアーミーナイフを持っていく。
I take a Swiss Army knife when I go camping.
アーミーナイフで段ボールを開けた。
I opened the cardboard box with a multipurpose knife.
十徳ナイフ is a more general term for a multi-tool knife, while アーミーナイフ specifically evokes the Swiss Army knife brand or military-style folding knife.
Borrowed from English 'army knife', referring to the Swiss Army knife or similar multipurpose folding knives.