The JFK ARC FAQ is just getting started, please come back in a week or so to see something more substantial.
What is … ?
The JFK ARC is the President John F. Kennedy Assassination Records Collection, usually referred to in this website as the ARC. It was established by 1992 and is now held by the National Archives and Record Administration.
The 1992 JFK Assassination Records Collection Act is the law which created the JFK ARC.
The ARRB is the Assassination Records Review Board. The ARRB was established by the Assassination Records Collection Act of 1992. Its purpose was to oversee the collection and release of government and private records relating to the 1963 assassination of President John F. Kennedy. See here for more information on the Board.
The National Archives and Record Administration is the depository for all permanent U.S. federal government records. The ARC is stored in NARA's College Park facility in Maryland. NARA's main webpage for the Collection is here.
The Assassination Collection Reference System is NARA's online database of identification aids for records in the JFK ARC. It is available here
What does … mean?
A record is "released" in the ARC when text within it is made public. Sometimes the word "opened" is also used with the same meaning. One record may be released more than once if different passages in it are released at different times. When no more text remains to be released, it is said to be open in full (OIF), or released in full (RIF). The opposite of "release" is "withhold".
"Withhold" means to keep text in a record from the public. (Sometimes the words "postponed" or "denied" are used with similar meanings.) "Withheld" text is usually redacted by being blacked out or whited out. Sometimes replacement text is used to indicate the general sense of the information withheld. Records can be withheld either in part (WIP) or in full (WIF). "Withhold" is the opposite of "release".
"Not believed relevant" is a designation adopted by the ARRB to speed up its review process. Approximately 800 CIA records were originally designated NBR. All of these are now open in full, or in part. See here for a longer discussion.
"Not assassination related" is an FBI designation, similar in meaning and purpose to the ARRB designation "NBR".
In addition to assassination records directly relating to the events and figures in the assassination, the ARRB also added many records to the ARC that it felt could "enhance historical understanding". Although the acronym EHU is not used in the ACRS, it occurs frequently in ARRB documents discussing which documents should be added to the collection. See for example the discussion in the ARRB Final Report here.
An SF-135 is also known as a Record Transmittal form. These forms describe files sent to storage and specify the date for destruction.
A Reader Information Form is the standard identification aid which is attached to most of the records in the ARC as a cover sheet. It provides document metadata, such as the originating agency, document type, date, release status, and so on. The RIF number is a unique 13 digit number for each document that has a RIF. See here for a more detailed introduction to RIFs.