A domain, or domain name, is a human-friendly identifier for a website or other online resource, acting as a user-friendly alternative to the numerical IP address. It’s the name you type into a browser to reach a specific website, like “yeticraft.net”.
You can purchase a domain through a Registrar such as Cloudflare, Namecheap, etc.
Running your own local domain is easy with a home-lab running a split DNS.