Bulk Domain Search
You can look at a domain name like the address of building! It's the way people find your business or home. When looking for a website, you type in the domain name and you get taken to it.
If we look to your domain name as an address, then your web hosting service is the actual, physical building. Once your domain name is set to point to your server, you'll get taken to the said website. If not for domain names, we would have to access websites by their IP addresses, which would be way too hard to memorise.
The general domain registration policy allows more than one domain to be assigned to one and the same entity, so there is no limit on the number of domain names that you, your organization or company can buy.