.us = United States, not commonly used.
Ideally, a URL ending in "com" indicates a commercial website whereas a URL ending in "net" meant that this site belonged to an organization involved in networking such as ISPs. In practice, people often chose a URL ending in .net when they couldn't get the one they wanted ending in .com.
.edu
i don't know either:(
it means education.
Is it a blog with a URL ending in .mu.nu such as everydaystranger.mu.nu?
.com
The pathname is the ending part of the URL. It is after the "slash" of the domain name.
If the URL ends with a .abw (notice the period "." before abw) that means a AbiWord document file is opened .
The ending ase indicates that the substance is a catalyst.
.edu Some countries have specific url suffix such as .school.nz or .ac.uk
.com
That would be .com which indicates a commercial web site. Companies or profitable organizations have this type of URL.