Graphviz
Graphviz (short for Graph Visualization Software) is a package of open-source tools initiated by AT&T Labs Research for drawing graphs specified in DOT language scripts. It also provides libraries for software applications to use the tools. Graphviz is free software licensed under the Eclipse Public License.
Software architecture
Graphviz consists of a graph description language named the DOT language and a set of tools that can generate and/or process DOT files:
Applications that use Graphviz
AsciiDoc can embed Graphviz syntax as a diagram.
ArgoUML's alternative UML Diagram rendering called argouml-graphviz.
Bison is able to output the grammar as dot for visualization of the language.
ConnectedText has a Graphviz plugin.
Doxygen uses Graphviz to generate diagrams including class hierarchies and collaboration for source code.
Essential (Enterprise Architecture) Project uses Graphviz within the reporting tool used to visualise Enterprise Architecture information captured in Protégé using an ontology that realises the Essential Project Enterprise Architecture metamodel .