"A person who is legally owned by someone else and has no personal freedom." (CD)
The graph displays the other subjects mentioned on the same pages as the subject "Enslaved people". If the same subject occurs on a page with "Enslaved people" more than once, it appears closer to "Enslaved people" on the graph, and is colored in a darker shade. The closer a subject is to the center, the more "related" the subjects are.