This is a common question which confuses a lot of new customers.
First, every site receives a site name when you start the site. The "hstrial...", is the default name that is assigned to every website when its started. To simplify the concept, just think of the site name as nothing more than a folder that holds the pages of your website.
Technically, the site name acts like a sub-domain with homestead.com (or intuit.com) and provides you with a way to access your site live on the internet even if you have not registered your own domain name.
The site name in this case points or directs visitors to the IP address of your website, which would look something like this: 184.108.40.206
This is Homestead's IP address and if you type it into your browser you'll see that it takes you to www.homestead.com just like your site name and domain name would.
Obviously nobody wants to try to remember a long numerical IP address to access a website (or the hstrial site name) which is why the DNS (domain name system) is in place. When you register your domain name it is nothing more than an alias for an IP address. This way you can use your domain name to market and advertise your website. In most cases nobody other than yourself will see the site name, unless you give it to people.
If your website is for a hobby or non-business and you don't want to register a domain name, you can change the sitename to something different if you wish.
To change your site name, log into your account and click Websites Manger on the left side of your screen. Then click the More link near the center of the page and choose "Rename this site" from the dropdown menu.