Directory - The part of a URL that identifies the location of the file in the web folders. In http://www.ibm.com/help/page.html, help is the directory.
Domain - The part of a URL that identifies the computer. In http://www.ibm.com/help/page.html, www.ibm.com is the domain.
Edge Pages - The edges are links that are not followed because they don't match the filter, or they are on a different site, or because they are going to level four when the program is told to stop at level three.
Levels - The number of clicks it would take to get to a page. If you enter a URL, and specify one level, it will only get that page. If you specified two levels, it would get that page and everything it links to. If you specified three levels, it would get that page, everything it links to, and everything those pages linked to. If you specified four levels... Well, you get the picture.
MIME type - A text identifier that is sent with web pages that identify the type of file. It might be text/plain, text/html, application/exe, etc.
Page - The part of a URL that identifies the file. In http://www.ibm.com/help/page.html, page.html is the page.
URL - A Uniform Resource Locator, sometimes known as a link. http://www.ibm.com/help/page.html is a URL.