A web page can be static or dynamic. Static pages, such as a regular HTML page that you might create with Dreamweaver, are those which have been created once and do not have to be regenerated every time a person visits it. In contrast, dynamic pages, such as those you create with WordPress, do need to be regenerated every time they are viewed; code for what to generate has been specified by the author, but not the actual page itself. These use extensive PHP code which is evaluated each time the page is visited, and the content is thus generated on the fly, upon each new visit.