also: じっとくナイフ
noun
multipurpose knife; Swiss Army knife
Refers to a folding knife with multiple tools, often modeled after the Swiss Army knife. 十徳 literally means 'ten virtues' or 'ten functions'.
キャンプには十徳ナイフを持っていくと便利だ。
It's handy to bring a Swiss Army knife when camping.
彼は十徳ナイフで缶を開けた。
He opened the can with a multipurpose knife.
アーミーナイフ is a direct loan from 'army knife' and often refers to a military-style knife, while 十徳ナイフ emphasizes the multi-function aspect.
十徳 (じゅっとく/じっとく, 'ten virtues/functions') + ナイフ ('knife'). The term 十徳 originally referred to a multi-purpose tool or a person with many skills, and here it describes a knife with many built-in tools.