The public domain has been mentioned a few times in this guide. What is it?
The term "public domain" refers to creative works that are not protected by intellectual property laws such as copyright, patent, or trademark laws. These works are considered public property, and anyone can use them for any purpose. The public domain serves as a rich repository of knowledge, culture, and creativity that can be freely accessed, shared, and built upon without the constraints of copyright regulations.
Watch this video from the U.S. Copyright Office about the public domain.