The main difference between the two is that an Addon Domain gets treated like a separate domain from the main or primary domains listed in cPanel.
This domain does not have its own unique address and acts as a domain that is mainly going to be used to be forward or redirected to another non-alias domain.
An example of this might be;
- Your Main Website: PandasGetLonelyToo.com.au
- Your Alias Domain: PandasGetLonelyToo.com
- The .com would then redirect to forward to .com.au
Another example might be;
- Your Main Website: pandasgetlonelytoo.com.au
- Your Alias Domain: pandasgetlonelyto.com.au
- pandasgetlonelyto.com.au forwards to pandasgetlonelytoo.com.au
This type of domain has the capability of holding its own website and other c00l things like Email Address/Accounts. When you add an Addon Domain in cPanel - It will create it own public_html folder which will be named after the domain that was just added (i.e if I add google.com then the folder will be called google.com).
Your Hosting Provider will tell you how many Addon Domains your cPanel or Plan is allowed to have and in theory you can have ‘that many' websites on your Hosting Account.