AP Stylebook entry
Keyword Slug Line
Filing the Wire: Keyword Slugline
Every news item in the AP report has a keyword section that consists of a cycle designator, a hyphen and a keyword or keywords. A comma marks the end of the section.
Because the keyword section provides the basic identification of a story for automatic linkup routines, it must be repeated in exactly the same form on all subsequent leads, etc., filed for a story.
The cycle designator is always BC-, to indicate that the story may be used in both morning and afternoon news cycles. For online services, this may switch to AP-.
The keyword or slug (sometimes more than one word) clearly indicates the content of the story. With crime stories, make sure the slug does not imply guilt before the completion of the trial.
Use of easily recognized abbreviations and acronyms is encouraged. (Also, the keyword of an item sent on a state service contains the postal code for the state of origin.)
Some computer systems automatically add a word count at the end of a line.