What is UML?
UML stands for Unified Modeling Language and is a modeling language for object-oriented (software) systems. The word software is in brackets here as the design and description of software systems was definitely the focus in the development of UML; in theory UML is actually suitable for modeling any systems using an object-oriented perspective. One example would be describing the IT-related aspects of a business domain as part of an object-oriented analysis, in order to derive requirements for a corresponding software system.
UML was presented in the mid-1990s by Grady Booch, Ivar Jacobson, and James Rumbaugh as a joint development of their own object-oriented methods (Booch method, OOSE, and OMT). Since 1997, UML has been published as a standard by the OMG and has been continuously developed. The OMG (Object Management Group) is a non-profit organization that is responsible for a range of important standards in the IT industry. In addition to UML, these include BPMN.
The current UML version at the time of this document's creation is 2.5. This is also the version supported by ARIS UML Designer 9 and higher. The corresponding UML specification is available from the OMG at the following address: https://www.omg.org/spec/uml/.