cPanel and Plesk offer multiple domain types that you can add in the control panel. It is not always clear what they are and what you can use them for. This article provides brief explanations and examples. For articles about how to set up the various domain types, see the links in the Related Articles section.
A subdomain creates an additional site that can have its own unique content without the need to register an additional domain. Subdomains place a prefix in front of the domain name followed by a dot to create the unique name. Typical uses for a subdomain are to identify different types of content at one domain: product sales at shop.example.com, a blog at blog.example.com or a webmail portal at webmail.example.com.
An addon domain is an additional registered domain that is hosted in the same account as the primary domain. Addon domains can have their own unique content. Addon domains do not need to be related to the primary domain in any way. A use for an addon domain could be for a developer to host multiple sites under development in one account.
A parked domain or alias is an additional registered domain that shows the same content as your primary domain. A use for a parked domain might be a legal firm that previously used example.com and now wants to add a recently introduced name like example.law. example.law would be a parked domain for example.com and would show the same website.