For our technical audience:
A Hotshot address is a hash of a public key.
For our non technical audience:
A Hotshot address is cryptographically linked to your encryption keys. You can’t change one without changing the other. So if you’re using the correct address you can be sure you are also using the correct encryption keys.
The reason we call it an address is so that it is easy to conceptually understand that if you use the wrong the address, it will go to the wrong place (just like mail).
If you send a message to the right address only the intended receiver has the ability to read the message.
You can make your Hotshot address public, it does not have to be kept secret like a password. A hacker cannot do anything malicious to you just by knowing your Hotshot address.