In its simplest form:
= use the web
some.machine.somewhere.com = either the name of the machine you are running apache on or the ip address (e.g., 127.0.01).
somedir = the name of a directory as explained below.
somepage.html = the name of the HTML file to be "served" to the user.
somedir is defined relative the DocumentRoot (and DocumentRoot is usually defined in your /etc/httpd/conf/httpd.conf file) so that if you have the line
Then the file somepage.html is actually located at
It gets more complicated if you are using virtual hosts, multiple domains. multiple IP addresses, and aliased directories, but I'm guessing that you're not doing that right now