Subdomains are subdivisions of a domain name that allow you to create separate website addresses under the main domain. They are used to organize and categorize content or create separate sections of a website. A subdomain is created by adding a prefix to the main domain name, separated by a dot.

For example, consider the main domain example.com. By creating a subdomain blog, the complete web address becomes blog.example.com. This subdomain can be used to host a separate blog section of the website.

Subdomains are often used to differentiate different areas or types of content within a website, such as store.example.com for an online store, forum.example.com for a discussion forum, or news.example.com for news articles.

Each subdomain can have its own unique content, separate FTP access, and sometimes even distinct design or functionality. It allows for easy organization and navigation of related content within a larger website.

From a technical standpoint, subdomains are treated as separate entities and can be hosted on different servers or configured with different settings. However, they still share the main domain's resources, such as the DNS configuration and SSL certificate.

Subdomains can be created and managed through the domain registrar or hosting provider's control panel, where you can set up DNS records and specify the content or server location for each subdomain.

Overall, subdomains provide a way to create distinct sections or categories within a website while maintaining a unified main domain.