DOT is a plain text graph

Graph (mathematics)

In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...

 description language. It is a simple way of describing graphs that both humans and computer programs can use. DOT graphs are typically file

Computer file

A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished...

s that end with the .gv (or .dot) extension. The .gv extension is preferred, as .dot also is used by Microsoft Office 2003

Microsoft Office 2003

Microsoft Office 2003 is a productivity suite written and distributed by Microsoft for their Windows operating system. Released on October 21, 2003, it was the successor to Office XP and the predecessor to Office 2007.- Overview :...

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Various programs can process DOT files. Some, like dot, neato, twopi, circo, fdp, and sfdp, will read a DOT file and render it in graphical form.