A Domain Alias (or Park Domain) allows additional domain names to all lead to the exact same locations on your original website. For example, if you are hosting your domain name “original.com” and added a Domain Alias for “alias.com”, then http://www.original.com and http://www.alias.com would take a visitor to the exact same pages of your original.com website.
http://original.com/somefile.html would bring someone to the exact same page as http://alias.com/somefile.html. With a Domain Alias, the URL in the address bar of the user’s browser stays exactly as they typed it.
Domain Aliases have all the properties of a regular domain hosting account in terms of DNS and mail. The only difference is that the Domain Alias has no files (web pages) of it’s own. Instead it uses the files of the aliased domain name.
Domain Alias is the same as Park domain, some web host prefer to use the term Domain alias over the other. Cpanel host however, uses the term Park domain.