You're comparing two completely different things here.
Wordpress is a content management system, which is a system of files that allows you to perform various tasks in a web environment. Wordpress allows you to do everything you want without needing any coding experience whatsoever. To add a page, you just click add page, type the content, and shizam. To update it, you just edit the content and shizam.
Dreamweaver on the other hand is an IDE (integrated development environment). It is a program used to code the files used in a web application (such as the files in Wordpress, for example).