I am assuming you want a definition here for some practical reason - for example, perhaps you want to loosen controls or approvals for some documentation that isn't "important".
Realistically, you need to read the standards you are applying and just ensure you meet the requirements within. Trying to generate a non-standard definition is probably counterproductive.
If you really want to be able to reason about it, it's better to think about quality-related activities. What are things that you do to ensure your product is good/safe/effective? This will include any processes mandated by your regulations and standards, any activities you need to do to implement those processes (e.g., testing quality systems software).
For each of those activities, you want to be able to prove you did them. Therefore, you will need documents and records - and those are the important ones to keep a hold of.
That's basically what you ask yourself - "Is this information needed to show that we are doing things properly, or needed to be available so that people know how to do things properly?". If the answer is yes, treat it like it's "quality". Trying to group "types" of documents is sidestepping the real crux. What is the document for? If you can answer that question, it should be obvious how you need to treat it.