Noun

1. The feature of intellectual property being not protected under patent or copyright, i.e. no person or other legal entity can establish proprietary interests.

   • "This book is in public domain"

2. Open land such as unowned prairie in the western and southwestern United States. Space not subject to a land patent.
3. Information about a subject which is accessible to anyone

   • "There is very little information about the treaty which is in the public domain."