Domain is the name of the site that is typed in the top of the browser in the address box and is accompanied by the required extension, such as. com .net org
and to understand more the domain is like this form www.yourname.com
com - net - org - info - tv -me - tel - be - de - name - us - im - in - eu - co.in - biz - co.uk - org.uk - me.uk - fr - so - asia - pro - ch - ws
And also there's a lot more.