Build Basics / Standard term
Domain name
A domain name is the human-readable web address, such as example.com, that visitors type to reach the server where your project lives. It maps to a numeric address (an internet protocol, or IP, address) so a browser knows which machine to contact.
A domain name is the human-readable web address, such as example.com, that visitors type to reach the server where your project lives. You rent it from a registrar, and it maps to a numeric internet protocol (IP) address so the browser knows which machine to contact. Say you deploy a to-do app and your host gives it a long default address like my-app-7f3k.onrender.com. You buy mytodos.com, point it at the host, and from then on people reach the same app by typing the name you chose. The domain is the label; the server is where the work happens.
Builder example
A memorable domain is how people find and trust what you built. If you deploy a support bot at a host's auto-generated address, the URL is hard to share and easy to mistype. Buying a domain and pointing it at the deployment gives you one stable name that survives a host change, since you can repoint the same domain at a new server later without asking anyone to update their bookmarks.
Common confusion: A domain name is the address people type; the server is the computer that answers. Buying a domain does not put anything online by itself. You still deploy your project to a host, then point the domain at that host so the name resolves to a running server.