Quick explanation of Wikipedia outlines Outline is short for hierarchical outline There are two types of outlines sentence outlines like those you made in school to plan a paper and topic outlines like the topical synopses that professors hand out at the beginning of a college course Outlines on Wikipedia are primarily topic outlines that serve 2 main purposes they provide taxonomical classification of subjects showing what topics belong to a subject and how they are related to each other via their placement in the tree structure and as subject based tables of contents linked to topics in the encyclopedia The hierarchy is maintained through the use of heading levels and indented bullets See Wikipedia Outlines for a more in depth explanation The Transhumanist