A subdomain is an extension to a main domain name that creates a separate web address within the same overall domain. For example, in 'forum.canuckduck.ca,' 'forum' is the subdomain of 'canuckduck.ca.' Organizations use subdomains to organize different sections or services—like 'mail.example.ca' for email services or 'support.example.ca' for help resources. Subdomains can be hosted on different servers or point to different applications while appearing as part of the main domain. Government organizations commonly use subdomains to organize services: 'permits.cityname.ca,' 'recreation.cityname.ca.' Subdomains require configuration in domain name system (DNS) settings. Unlike separate domains, subdomains maintain association with the parent domain for branding and organizational clarity.