One page on a website can link to multiple websites thus creating multiple backlinks. It says it in pretty plain english.
ever seen a article with 2 links in it?
AFAIK 1 page can have multiple backlinks.
So if you put a comment in a comment box with your link, that will count as 1 linking page, 1 backlink and 1 linking domain.
If you write your second comment in the same comment box with another link, it won't won't as another linking page or domain but it may count as the 2nd backlink.
So that is the grand total of backlinks.