ADOxx has two pre-defined meta models, which are used to define an own meta model by inheriting from the pre-defined meta model classes.
One pre-defined meta model implements a directed graph, hence those pre-defined classes are used to define business-processes, workflows, petri-nets and the like.
The second pre-defined meta model implements organizational structure similar to a tree. Hence it is used for class diagrams, organizational structures and the like.

Typical focus in the tutorial is in starting the development environment, defining the first simple meta models (e.g. a simple Entity Relationship model) and learn the ADOxx meta meta model concepts such as model type, classes, abstract classes, graphical notation, attribute definition, attribute types, and the like.

See slide set: http://www.adoxx.org/live/documents/10157/28257/1.+Realising+a+Modelling+Language.zip/0a6183cc-fa83-42b3-a653-8ee37834676b

So the answer is: ADOxx provides the necessary concepts and tools to defining meta models like ERM, OWL, BPEL, petri-nets, UML or similar one and create full-fletched modeling toolkits.