Communities often define themselves by vocabulary that those in the inner circle know, and those on the outside do not. Security people do this as well, and sometimes more than most. We are, after all, the professionally paranoid, and it is more important to us than to most other groups to know who belongs.

This linguistic identification can backfire. Law enforcement personnel have a specific and distinctive vocabulary all their own. I have been informed by a number of members of police forces that police officers are very susceptible to social engineering, or scams, due to this fact. If you know the language, you must be one of us.

Understanding the language of the security community is made more difficult because there are multiple security communities. Security people come from backgrounds such as the military, government, academia, industry, system administration, law enforcement, and the intelligence community. Very often, these groups don t talk to each other.

In terms of the security lexicon, the first contribution has to be the government and military, particularly from the United States. A number of terms arose from the language developed in that arena, and the formal studies funded from that source. Several of those definitions are included here. Usage has fallen off, in the face of new technologies and use, but they may be of historical interest, and still have force in security literature overall.

The Internet and networking technologies have become major factors in security. While the older security functions and concepts are still...