"In the U.S., an official whose job is to be in charge of performing the orders of the law courts and making certain that the laws are obeyed within a particular county." (CD)
The graph displays the other subjects mentioned on the same pages as the subject "Sheriffs". If the same subject occurs on a page with "Sheriffs" more than once, it appears closer to "Sheriffs" on the graph, and is colored in a darker shade. The closer a subject is to the center, the more "related" the subjects are.