Domains consist of several parts that have different names. Here's a typical example of what it looks like:
www.menabitt.com
www is an abbreviation for this is a web address. It's a common subdomain, but many other things can appear in its place.
menabitt is the exclusive name of the domain, which usually represents the name of the company, site, person, or any information you want the visitor to remember.
.com is the domain extension, and it may vary according to the geographical area, the field of the website, and many others.