Definition An Alias Domain is a domain name that can be used as an alternate name for another domain. For example, if you have two domain names pointing to your website, you can “map” the second domain as an “Alias” of the primary domain. Website visitors will see the Alias in their URL bar when navigating the site. Relevance to WordPress When you have a WordPress website (or website of any kind), you can assign Aliases to your website. However, not all servers are ready “out-of-the-box” to map domains to a single website and require additional configuration. Furthermore, your WordPress website needs some extra configuration to “map” each alias to a specific “post” in WordPress (or group of posts). Posts can include any default post type that comes out of the box with WordPress, like Pages, Posts, Products, etc, or any Custom Post Type created by other plugins or themes. End Goal: Multiple domains on a single WordPress site At the end of the day, the purpose of creating an Alias domain on your server is to map multiple domains to a single WordPress installation. Domain Mapping System let’s you handle the mapping of domains to specific posts after you’ve set up your server properly.