Difference between ethernet address and IP address?

Hey
Can anyone please tell me what is ethernet address and its role in security. If someone knows my PC ethernet address, how would it affect my security? What can he do with that ethernet address?
I have some knowledge about IP address, many ways of tracing and hiding IP, but I don't know if ethernet address can also be traced. I really wanna know ethernet address is useful for what purpose? Thanks for any help.

And here's the answers FWIW

An IP address is just a pointer to a location on a network. Whether that be a local network, or the internet. When you say "ethernet address", I'm assuming you refer to your IP address on your local area network.

There are 3 groups of reserved IP address space for private networks, these cannot be used as an internet IP. They are:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

So your Ethernet IP is the address of your computer on your local network. Other computers and devices on the network will have a similar IP. For example a common one is to have 192.168.1.1 as your router/modem IP, and 192.168.1.X as your PCs IP.

As for security, there is really no issues with people knowing it. If someone knows it, they know how to find your computer on your network. But you should have appropriate security measures in place to protect your network in the first place. And even if you don't, they would still have to physically connect to your local network to do anything with it!

Your ethernet address (or MAC address) is a unique identifier to your machine, printer, etc. It doesn't make it out very far. Even if someone knows your MAC address, that knowledge certainly doesn't help anyone do anything either good or bad.

Ip Address is changeable while ethernet is not.
Ethernet is also called as MAC address(Media Access Control).
Ethernet is physical address while Ip is logical address.