A "hit" is any HTTP request for any content on your website.
A visit, is when a unique IP browses your website for a certain amount of time.
A visit may consist of multiple page views, which may in turn comprise multiple hits (e.g. each page is a hit in itself, and then each page will have images, javascript, stylesheets).
So one visit may well equal 5 page views which may well be 50-100 "hits".