When I say "consciousness", the concept that I mean isn't reducible to other concepts. It's a concept that can only be found through introspection. And it seems like many have noticed the same concept, so we can label it with a word. But we can't define it such that someone who hasn't already noticed the concept will understand it. We can only describe it in such a way that those who already noticed it can confirm we're talking about the same thing. I think the parent's comment has done this adequately, and I don't think it's a problem that the definition is incomplete.