Messages authored within the US Department of State’s “cable” system all receive abbreviations that play a role similar to the “tags” that bloggers often apply to their posts. For researchers (including linguists and reporters) who are interested in reading these cables, TAGs are a valuable way to cluster several different cables on a similar topic. For instance, it might be interesting for a linguist to isolate all of the cables bearing the “PTER” tag (“PTER” stands for “Terrorism”). The Department of State has defined some but not all of these TAGs. Read on to learn more about the DoS system, and a corpus analysis method for determining the meaning of TAGs that were formerly undefined.