Multiple domain names for one site

What if you have two domain names: one is the name of the company, the other is the type of product the company sells, and you want viewers to access the site by either domain name, keeping the domain name they used in the address bar?

If you “park” one of the domain names, it seems that the hosting technology will roll it over to the primary domain. The result is that as a viewer browses the site a different domain than the one they typed is what shows in the address bar.

Is there a way to keep the domain name they entered for each URL on the site?

What you’re trying to do is called Domain Masking. There are several ways to achieve this, but they are not easy.

There is a plugin in the repo that seems to be able to do content masking right from within the dashboard, but I have never tested it.

My initial intuition would be to do it using htaccess and apache’s mod_rewrite module. You can see an example here, and there are plenty of similar questions/answers on stackechange which you can google.