Public Domain
Public Domain is a copyright term that is often used when talking about copyright for creative works. Under U.S. copyright law, individual items that are in the public domain are items that are no longer protected by copyright law. This means that you do not need to request permission to re-use, re-publish or even change a copy of the item. Items enter the public domain under U.S. copyright law for a number of reasons: the original copyright may have expired; the item was created by the U.S. Federal Government or other governmental entity that views the things it creates as in the public domain; the work was never protected by copyright for some other reason related to how it was produced (for example, it was a speech that wasn't written down or recorded); or the work doesn't have enough originality to make it eligible for copyright protection.
Citation
Hollem, Howard R.. Chicago, Illinois. Subsistence research laboratory of the U.S. Army quartermaster depot. K ration is highly concentrated, and is used only in time of emergency and continuous combat when regular messing facilities are not available. Packed in three boxes for three meals, it weighs only 32.86 oz. and contains 3,726 calories. It is so packed that it will not be affected by temperatures up to 135-F or down to 20 below zero. March 1943. Photograph. Library of Congress. Accessed February 20, 2026.