What is "outliner"

n. (context computing English) A software system for organizing text into a hierarchy.

An outliner (or outline processor) is a specialized type of word processor used to create, build, modify, and maintain outlines. It is a computer program, or part of one, used for displaying, organizing, and editing hierarchically arranged text in an outline's tree structure. Textual information is contained in discrete sections called "nodes", which are arranged according to their topic-subtopic (parent-child) relationships, sort of like the members of a family tree. When loaded into an outliner, an outline may be collapsed or expanded to display as few or as many levels as desired.

Outliners are used for storing and retrieving textual information, with terms, phrases, sentences, or paragraphs attached to a tree. So rather than being arranged by document, information is arranged by topic or content. An outline in an outliner may contain as many topics as desired. This eliminates the need to have separate documents, as outlines easily include other outlines just by adding to the tree.

The main difference between a hand-written outline and a digital one, is that the former is usually limited to a summary or blueprint of a planned document, while the latter may easily include all of the content of the entire document and many more. In other words, as a hand-written work an outline is a writing tool, but on a computer, it is a general purpose format supported by a robust development and display medium capable of handling knowledge from its creation to its end use.

Outliners may be used in content creation instead of general word processors for capturing, organizing, editing, and displaying knowledge or general textual information. Outliners are ideal for managing lists, organizing facts and ideas, and for writing computer programs. They are also used for goal and task management (including personal information management and project management), and for writing books and movie scripts.

The graphical counterpart to outliners are mind mappers.