A "static" page usually means one that you have coded yourself and uploaded, such as mypage.html. It doesn't change when on the server, and there is little or no user interaction, apart from basic things like clicking links.
A "dynamic" page is one that has more functionality and can be updated without you recoding it. For example, it might be a page that allows users to post comments. In a case like this, there are things going on in the background, such as PHP interacting with a database to make changes to the page without you doing anything.