metamodel

A metamodel is at a higher level of abstraction than a model. It is often called “a model of a model“. It provides the rules/grammar for the modelling language (ML) itself. The ML consists of instances of concepts in the metamodel
A metamodel describes the rules and constraints of metatypes and metarelationships
Concrete metatypes are instantiated for use in regular modelling work.

In object-oriented programming, a metaclass is a class whose instances are classes. Just as an ordinary class defines the behavior of certain objects, a metaclass defines the behavior of certain classes and their instances.