Awstats give website statistics per month in the following format:

The difference between these are as follows:

Unique visitors are measured by IP address. So if people visited your site from shared IP addresses, such as at an internet café, or sometimes through a shared proxy server in a big corporate, the visit would only be counted once as a 'unique visitor'.

That is why you have the 'Number of visits' statistic as well. So if two people using an Internet café visited your site, you will have one unique visit, but two visits.

Pages are the number of pages that were viewed on your site by all the visitors. So that is why you have the statistic that tells you : 5.74 Pages/Visit. So each visit(or) opened 5 or so pages on the site.

Hits is a completely unreliable and confusing statistic to try and measure activity on your site. Each and every time that an element on your web pages, such as the graphics, the text, etc is opened and viewed, each and every one of those elements count as a 'hit'. So you can have two pages, one with just text, the other with a picture gallery with 100 pictures, the one page will contribute one 'hit' to the statistics, and the other page will contribute '100'. This is a bit simplified, but the principle remains the same. Number of Hits should therefore really be ignored if you are looking to see how much traffic your are getting, and in fact, if anyone tells you that they are getting millions of hits on their site, you can also safely discount that as meaning anything!

So basically you have to look at both Unique visitors and Number of visits to get an idea of how popular your site is.