Each file sent to a browser by a web server is an individual hit. Whereas, a pageview is each time a visitor views a page on your website, regardless of how many hits are generated. Pages are comprised of files. Every image in a page is a separate file. When a visitor looks at a page (a pageview), they may see numerous images, graphics, pictures etc. and generate multiple hits. For example, if you have a page with 10 pictures, then a request to a server to view that page generates 11 hits (10 for the pictures, and one for the html file). A page view can contain hundreds of hits.
So, don't get mislead into thinking that the site got ten of thousands visits a day when a portal/website sales rep boast about his/her site popularity by referring the "Hits" figure on the stats to you.