Index or homepage - which is which?

I noticed that in a lot of the modules/settings there are references to both, amount of items on the index page as well as amount of items on the homepage. Well, if the homepage is the startup page of D7, then what's the reference to the index page all about? Is that the startup page of a member once he or she is signed in? It would be tremendously helpful to have popup aids in some sections.

index of most sites are the 'homepage'. unless edited from httpd.conf specifying which file is to be index of the site. as a standard, index.ext is the leading page 'homepage' of a site.

Regards,

DosDawg