noun, noun which may take the genitive case particle 'no'
Refers to heavy metal plating used for protection, especially on warships or armored vehicles. Also used attributively with の.
戦艦の甲鉄は厚さが数十センチもあった。
The battleship's armor plate was several tens of centimeters thick.
甲鉄の扉が閉まると、中は完全な密室になった。
When the armored door closed, the inside became a completely sealed room.