Subdomain

(sub d -m n ) (n.) Also called a child domain, a domain that is part of a larger domain name in DNS hierarchy. DNS hierarchy consists of the root-level domain at the top, underneath which are the top-level domains, followed by second-level domains and finally subdomains. For example, in the domain name webopedia.internet.com, “webopedia” is a subdomain of the larger second-level domain “internet.com.”