A weapon, typically a knife or blade of 2-6 inches easily concealed but also pertaining to any weapon made of metal, usually bladed from a trench spike to a sword.
Can also be used to describe a handgun
From Kill Bill:
Hattori Hanzo: What brings you to Okinawa?
The Bride: I'm here to see a man.
Hattori Hanzo: Oh yeah? You have a friend living in Okinawa?
The Bride: Not quite.
Hattori Hanzo: Not a friend?
The Bride: I've never met him.
Hattori Hanzo: Never? Who is he, may I ask?
The Bride: Hattori Hanzo.
Hattori Hanzo:
Serious, switches to Japanese What do you want with Hattori Hanzo?
The Bride:
Japanese I need Japanese steel.
Hattori Hanzo:
Japanese Why do you need Japanese steel?
The Bride:
Japanese I have vermin to kill.
Hattori Hanzo:
English You must have big rats if you need Hattori Hanzo's steel.
The Bride:
English ... Huge.