What is a domain alias (parked/addon domain)?

A domain alias (sometimes called a parked domain or addon domain, depending on the hosting provider) is an extra domain that shows the same content as a hosting account's main domain, without having its own separate space.

It's useful when you own several domain names (for example the .ro and .com versions of the same brand) and want all of them to display the same site, without paying for a separate hosting plan for each one.

It differs from a subdomain in that it is a standalone domain name, registered separately with the registry, just connected to the same hosting account.