WordPress describes itself as, "an online, open source website creation tool written in PHP. But in non-geek speak, it's probably the easiest and most powerful blogging and website content management system (or CMS) in existence today."
WordPress is a widely popular blog or website builder that allows you to build a professional looking site using a variety of modern design templates and easy-to-use content management tools. There are thousands of templates, called Themes, offered, both for free and for purchase, that allow you to customize your site design and functionality. These themes, as well as a large selection of plugins and widgets, are available for download and use.
For a more detailed look at what WordPress has to offer, visit Wordpress.org.