What is meant by an context-free-diagram?

The term "context-free diagram" is not a standard term in computer science, linguistics, or any other field. It seems likely that you might be encountering a specific terminology used within a particular context.

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* Where did you encounter this term? (e.g., a book, website, lecture)

* What was the context of the term? (e.g., what were they describing or explaining?)

* Can you provide any examples or further explanation?

With more context, I can help you understand what the term might mean and provide a relevant response.