Subdomain

Subdomains are everything before the main domain.

Technically, www., is a subdomain, and website addresses, or URLs, without any subdomain, are also known as the root or naked domain.

For other subdomains, commonly they will be names to indicate the part or service offered at that address, examples include: app., cloud., status., dash., portal., dev., and many others.

For search engine optimisation purposes, there are differences in the way subdomains and subdirectories are indexed and ranked, with subdomains seen as separate websites, with their own independent ranking authority and rating.