How can I give a 'name' to a sever and not have to access it through IP address?

For example, I want to host a web-app at x.x.x.x:3838. I want to be able to access this simply if I type in 'dashboard/' as the URL (assuming the user is on the correct internet). I'm having trouble finding the right answer because I don't know terminology and thus my searches aren't very fruitful.