What does 'meta' mean? What is meta-language?

Thanks to Ms Langley's Year 11 English class for this Wordle

The prefix meta - as in metalanguage, metanarrative etc - is very difficult to pin down. In broad terms meta means 'about itself' - so metalanguage is the language of language. For example a language teacher might use metalanguage like lexicon or past perfect in a lesson plan.

This is reasonably comprehensible, though some might argue that a less fancy-pants alternative would be technical-terms or even jargon. It could also be argued that unlike other words with the meta prefix (see metatnarrative) metalanguage has at least the advantage of precision e.g. teachers should avoid using complex metalanguage in the classroom. And it can be useful for teaching identifying the concepts that underpin language learning.

What is a meme?
What is a metanarrative?
Mrs Langley's English Class Wiki