There’s a bit of leeway here, since that’s the word used in a different sense. But I would say that if you ask someone to “define what a chair is” that the word is being used in one sense only, compared to what happens when you ask someone to “define what ‘chair’ means” which is about the word.

That is, when we refer to a word like “chair” we use quotes, but without the quotes, we can say that an accounting department chair is not a chair.

Alternatively, we could analyze “accounting department chair” as a use of metonymy.