A subdomain is a subdivision of a larger domain, typically used to organize and categorize content on a website. It is represented by a prefix before the main domain name, separated by a dot, and can be customized to create a unique web address. Subdomains are commonly used to create separate sections for different languages, products, or services within a single website. They allow for easier navigation and management of content, providing a more streamlined and organized user experience. In essence, a subdomain acts as a virtual neighborhood within a larger online community, providing a designated space for specific content or functionality.