Context free Grammar and regular set
A context-free grammar is just a string such as "$A\to 0A0\mid 1A1\mid 0\mid 1$".  Forget for the moment that such a string happens to define a language (in this case, the set of all odd-length binary palindromes) and focus on the fact that it's a string over some alphabet.

Now, let $L$ be the set of strings that are regular grammars.  A set of strings is a language.  The question is asking if $L$&nbsp;is a regular language.