A hit is a request for a file from a Web server. This includes every stylesheet, javascript file, and image on a Web page. And as such is a bad metric to use for evaluating Web page popularity.
Web server analytics that show you only the number of hits that a site gets are not giving you a lot of information. In fact, a single Web page can generate dozens or possibly hundreds of hits to the server. And if you judge a site's popularity on the number of hits it gets, you'll most likely be very disappointed unless your Web pages are very plain, with no CSS, scripts or images. A much better metric to use is the pageview.
Hits are a valuable metric for Web server administrators. They can tell an admin how hard a server is being worked, and give him or her an idea of when the hardware will need to be upgraded.