I was exasperating my online friends when I started doing online stuff. This is because I don't know any internet terms and jargon. They either laughed or get frustrated when I do not even know how to copy and paste words or sentences. Anyway, that was some milleniums ago in cyberworld. Not that I have learned much but I can get by asking the "right" questions if I am stuck with something. And recently I have my own domain for my blog too. Though the set up part was done by my brother.
Domain name is likened to your online identity. The link that has your personal chosen name or company name that appears on the address bar at the top. There are two parts of a domain. The domain name proper and the top level domain extension (.com .net .org .info) After registering your domain with a reputable company, you will need to make a web hosting choice to host that domain and your website for you. That will make your site "live" on the internet.
Some web hosting companies will register your domain for you so that you don't have to do it separately.