BfV -- Federal Office for the Protection of the Constitution. This is Germany's domestic intelligence agency and it cooperates closely with the NSA. In addition to the federal office, there are state offices in each of Germany's 16 states, all of which work closely with the BfV.
BND -- The Bundesnachrichtendienst, Germany's foreign intelligence agency. It cooperates closely with the NSA, particularly on counter-terrorism.
Boundless Informant -- This NSA computer program generates heat maps displaying the amount of metadata the NSA has at its disposal at any given time and can be sorted by country. The display is color coded, with green indicating a lower amount of data and red showing a high amount.
BSI -- The Federal Office for Information Security. Once a part of the BND, this agency works under the auspices of Germany's Interior Ministry. It is responsible for the protection of government networks, among other duties.
CCE -- Center for Content Extraction. A department of the NSA, the CCE is responsible for the automatic analysis and filtering of text documents.
CSS -- Central Security Service. The military arm of the NSA, responsible for the exchange of information and coordination with the military. The head of NSA also leads CSS.
CT -- Counter-terrorism
DNI -- Digital Network Intelligence. This refers to the monitoring of digital communications such as emails, FTP, chat and the activities of routers and other networks. DNI can also be used as an abbreviation for Director of National Intelligence, the secret service coordinator in the White House.
ECC -- European Cryptologic Center. Established in 2011 as the successor organization to the European Security Operations Center (ESOC), it is located in the Dagger Complex near Griesheim and had 240 employees when it opened.
ETC -- The European Technical Center in Wiesbaden. It is the NSA's European communications headquarters and was modernized in 2011.
FVEY -- Denotes documents that can be shared within the "Five Eyes" intelligence alliance, to which the US, Great Britain, New Zealand, Australia and Canada belong.
GCHQ -- Government Communications Headquarters, the British intelligence agency and a partner of the NSA within the Five Eyes alliance.
JSA -- Joint SigInt Activity. Denotes the technical surveillance partnership between the NSA and BND in Bad Aibling.
NOFORN -- Abbreviation for "no foreigners," meaning the documents can only be seen by US citizens.
NSA -- The National Security Agency
OPSEC -- Operations Security. This refers to the protection of important information from enemies, hackers and spies.
PRISM -- The NSA program with allows agencies to access information from at least nine large American providers such as Google, Facebook and Apple.
SCS -- Special Collection Service. A unit operated jointly by NSA and CIA personnel that performs technical surveillance out of US embassies and consulates around the world. The number of SCS sites varies. As of 2013, there were 80, including in Frankfurt and Berlin.
SELECTOR -- Entries such as telephone numbers and email addresses targeted by surveillance.
SID -- Signals Intelligence Directorate. This is an NSA department that is responsible for collection, analysis and dispersal of information and intelligence.
SIGAD -- SigInt Activity Designator. Refers to signals intelligence producers and sources. The PRISM program, for example, is designated as SIGAD US-984XN.
SIGDEV -- Abbreviation for SIGINT Development, the systematic acquisition of new SIGINT sources.
SIGINT -- Signals Intelligence. This refers to the acquisition of intelligence via the surveillance of electronic signals, such as intercepting satellite communications or tapping into Internet data streams.
SUSLAG -- Special US Liaison Activity Germany, the NSA's liaison office in Germany. Since 2004, it has been located in the Mangfall Kaserne in Bad Aibling.
TEMPORA -- This is the name of a British surveillance program that intercepts global data traffic at major hubs and saves some of it temporarily. The NSA and GCHQ work closely together in analyzing the data.
TS -- Abbreviation for Top Secret
WHARPDRIVE -- A joint operation of the NSA and BND along with a third partner to access international data streams.
XKeyscore -- Software that allows analysts to search for possible targets before they have been formally identified. It can encompass all data received ("full take") and can rapidly access usernames and passwords.