元系统在不同领域有不同定义，大多都围绕者系统和元这两个词。

大致来看，元系统是一个由一大堆有着共同特质但是却本身有着不同属性的系统组合。在某些学者看来，元系统并不全等于自创生理论中的系统的系统。

Meta-systems have several definitions. In general, they link the concepts "system" and "meta-". A "meta-system" is a system about other systems, such as describing, generalizing, modelling, or analyzing the other system(s).

According to Turchin and Joslyn (1997), this "natural" systemic definition is not sufficient for their Theory of Meta-system Transition, it also is not equivalent to the definition of system of systems in Autopoietic Systems Theory.