Your scalp is the skin under the hair on your head.

To scalp someone means to remove the skin and hair from the top of their head.

A scalp is the piece of skin and hair that is removed when someone is scalped.

If you say that you want someone's scalp, you mean that you want to defeat or punish them.

If someone scalps tickets, they sell them outside a sports ground or theatre, usually for more than their original value.