Anything that is not protected by copyright is in the public domain. This includes:
- Unprotectable subject matter (facts, information, ideas, methods, processes, inventions, titles, names, slogans, short phrases, common geometric shapes, familiar symbols, unoriginal compilations systems (e.g., ordering things alphabetically), works created by U.S. government employees, natural objects formed or shaped by natural forces without human involvement (e.g., driftwood); works created by nonhuman animals; machine-generated output and AI-generated output except to the extent of the human contribution to it;
- Works that are no longer protected by copyright due to the expiration of the term of copyright;
- Works with copyrights that have lapsed due to failure to renew the copyright at a time when renewal was required;
- Works with copyrights that have lapsed due to failure to comply with a copyright requirement that existed at the time, such as failure to affix a copyright notice to a copy of a work that was published and printed prior to 1989;
- Works that have been dedicated to the public domain by the copyright owner.