Computers on the internet find each other using numeric addresses. A domain name is a human-readable stand-in for one of those addresses — example.com instead of a string of numbers nobody could remember.
Every server on the internet has an IP address — a number like 192.0.2.10 that identifies it. That is what computers actually use to find each other. A domain name exists purely for humans; DNS, covered in the next few lessons, is the system that translates the name back into the number a computer needs.
Domain names are registered in a shared global system, coordinated so that a given name — example.com — can only belong to one person or organisation at a time. Registering one reserves it for you, for as long as you keep renewing it.
Renting, not owning
You never truly "own" a domain the way you own a physical object. You are renting the exclusive right to use that name for a period of time — typically renewed yearly — from the registry system. Miss a renewal and it can become available for someone else to register, sometimes within days.
On its own, a registered domain gives you exactly one thing: the exclusive right to that name, and the ability to say where it should point. It does not, by itself, host a website, send email, or do anything visible — it is inert until you connect it to hosting (for a website) and mail servers (for email), both covered later in this category.
You will often see the same brand with different domains — example.com, example.in, example.co. These are genuinely different domains, registered separately, each pointing wherever its owner configures it to. Owning one does not automatically grant any of the others; a business protecting its name often registers several deliberately.
The next lesson breaks a domain name down into its actual parts — what the "www", the name itself, and the ending all mean structurally — followed by the different categories of endings and what registering one actually involves.