Excerpt from Enterprise Architecture Fundamentals:
Just as models represent sets of actual instances that correspond to categories deemed relevant, meta-models represent sets of categories appearing in sets of models; e.g., a meta-category could represent all categories of interfaces supporting communication in natural language. Using the modeling paradigm introduced in part I, a simplified meta-model would look something like this:
Meta-models can characterize models using any kind of criteria at any level of representation (figure 8-2): with the sky as the limit, some are effectively aligned with the models of concern (e.g., relational databases, a), whereas others are too abstract to be of any use (b, c).
For enterprise architects, the challenge is therefore to align meta-models with contexts and concerns. On that account, three different approaches can be consid- ered: patterns, profiles, and meta-languages.