Second-level domain

So, imagine a website is like a house. The domain name is like the address of the house. Now, the second-level domain is like the name of the family who lives in the house.

Let's take an example: www.google.com. Here, "google" is the second-level domain. It is the name of the family who lives in the house whose address is www.google.com.

Just like there can be many families living on the same street with different names, there can be many websites with different second-level domains under the same top-level domain (like .com, .org, .edu, etc).

For example, www.microsoft.com and www.amazon.com are two different websites under the same top-level domain (.com). They are like two different families living on the same street with different names.