1. Steel with a surface that is much harder than the interior metal

Type of: steel

• Mustela putorius
• Mustela rixosa
• Mustela vison
• mustelid
• Mustelidae
• musteline
• musteline mammal
• Mustelus
• Mustelus canis
• Mustelus mustelus
• Mustelus norrisi
• muster
• muster call
• muster in
• muster out
• muster roll
• muster up
• musth
• mustily
• mustiness
• mustn't
• musty
• mutability
• mutable
• mutableness