A website that features gathered and categorized information on other websites on the net. Sort of like a search engine but not quite the same, because it only "bookmarks" sites. Also, the sites are hand picked, so only the best of them get to be listed.
A website that list other websites in their various categories by location, industry or specialization. They dont utilize spiders to index Web sites. They often involve an editorial review by a human editor who will visit your Web site after you submit to the directory. For example: DMOZ
I define Internet finding aids that are arranged by subject and include only selected sites as directories. While they often do have keyword searching, all entries are listed under one or more subject headings.