Defense Security Service

Terms and Definitions of Interest for Counterintelligence Professionals


This Glossary is designed to be a reference for counterintelligence (CI) professionals within the Department of Defense (DoD); however other CI professionals may find it of use. It provides a comprehensive compilation of unclassified terms that may be encountered when dealing with the dynamic discipline of counterintelligence and related activities. Where some words may several meanings within the counterintelligence or intelligence context, a variety of definitions are included.

Defense Security Service Guide to Marking Classified Information

This guide gives Department of Defense (DoD) staff and contractors an overview of the kinds of marking required to protect classified and unclassified controlled information that cannot be disseminated to all audiences. The guide offers an integrated approach to the major requirements for marking and control of information, briefly explaining the reasons for marking and providing examples of correctly marked information. To facilitate information sharing and declassification processes, whenever practicable a classified attachment, addendum, annex, enclosure, or similar section shall be used when classified information constitutes only a small portion of an otherwise unclassified document.