what does url already exists means?

On doing directory submission, you must have encountered a message
while doing it "url already exists in directory" what does that mean?, it means that site is already listed in directory or submission have been done,now waiting for approval.

Most of the people skip that directory,but you can still submit your site into that directory in a category different than previous one. For instance, if you have submitted your site into travel->hotel category on first time, you can submit your site into Business->Business Services category next time.Most of the sites accept sites in multiple categories. They mention in their guidelines which most people do not read.

On second submission if your site is still giving the same message ( url already exists) then skip that directory there is no use submitting your site into it.