to penetrate (pierce) lead


Senior Member
In Superman comics, the only thing Superman couldn't penetrate (pierce) was lead.

Source: 504 essential words by Murray Bromberg (No more context)

What does "lead" mean in this context? It has may meanings in the dictionaries. I'm confused which definition it is in my context.

Thank you.
  • dojibear

    Senior Member
    US English
    "Lead" is a metal. It is heavy and common. It is used for many things.

    In Superman comics, Superman has "x-ray vision". That means he can see through objects. But he cannot see through lead.

    His vision cannot penetrate lead (He cannot see through lead).

    He can "penetrate" (break through) something made of lead.