WordPress is not WordPress.com
The domain ending .com is not optional as it is usually—it is a key differentiator.
Omitting “.com” when you mean to refer to WordPress.com is as inaccurate as omitting “wash” when you mean to refer to “car wash”. The two are not the same.
WordPress is a Free Software project
WordPress lives and grows on WordPress.org.
Thousands of volunteers contribute to its development, translation, community events, and many other aspects. The software itself is licensed under the GNU General Public License and comes with Four Freedoms.
WordPress is yours for the making
WordPress, the software, can be downloaded and customised.
You can download a .zip file from the home of WordPress, extract what is inside, install it on a web server, and make a website with it—free of charge. You will have to pay a fee to a third-party hosting provider of your choice for your own domain and server space. Your data is always yours.
WordPress is a trademark
The use of “WordPress”, the trademark, is overseen and protected by the WordPress Foundation.
No one is allowed to use the term “WordPress” for any commercial purposes without explicit permission from the WordPress Foundation. According to the WordPress domain policy no one is allowed to use the term “wordpress” in any top-level domain. Exemptions are the WordPress project itself, the WordPress Foundation, and—WordPress.com.