Any request made to the server which is logged, is considered a 'hit'.
Each valid line in the server log is counted as a hit. This number represents the total number of requests that were made to the server during the specified report period. Some requests made to the server, require that the server then send something back to the requesting client, such as a html page or graphic image. When this happens, it is considered a 'file' and the files total is incremented. The relationship between 'hits' and 'files' can be thought of as 'incoming requests' and 'outgoing responses'.