In terms of classification, what does "classified information" refer to?

"Classified information" refers specifically to information that is owned by the U.S. Government, and whose unauthorized disclosure could harm national security. This definition underscores the significance of safeguarding certain types of information so that its release does not pose risks to national defense or security interests.

The classification system is designed as a means of protecting sensitive information that could cause varying degrees of harm if disclosed—ranging from mild to severe impacts on national security. This information can encompass a wide array of topics, including intelligence operations, diplomatic communications, and technological data that, if exposed, might jeopardize the safety of citizens or the integrity of military and government operations.

Understanding this definition is crucial as it also delineates classified information from unclassified or publicly available information. Other options presented in the question do not accurately encapsulate what it means for information to be classified and therefore do not reflect the criteria used to define its sensitivity and the corresponding need for protection.