WordPress Web Design Glossary
Domain names are human-readable words, mapped to a web address, usually a website, where a visitor can direct their browser to go. Think of a domain name like a building address that you would like to drive to.
Domain names are registered as domain.domain+extension, such as getwebmax.com. Domain names can have subdomain names such as shop.getwebmax.com, help.getwebmax.com etc. For a full explanation of domain names, see Domain Name Wikipedia