What is a Subdomain?
A subdomain is a prefix that appears before the main domain in a URL. For example, blog.example.com, store.example.com、 と support.example.com are subdomains of example.com.
Businesses and bloggers typically use subdomains to host content they do not want or cannot host on their main domain. This content is usually in a different format or intended for a separate audience from the one on the main domain. However, the business or blogger wants their visitors to know they own the site hosted on the subdomain.
For example, a computer manufacturer with a site at example.com may host its support service at support.example.com. That way, the subdomain gives the support site enough credibility while preventing the brand from including unrelated user-generated content on its main site.