I'm not an expert on the difference, but informally, I'd say that the difference is this: a "document" will have more and/or larger passages of text, and the fi

I'm not an expert on the difference, but informally, I'd say that the difference is this: a "document" will have more and/or larger passages of text, and the fields are mainly meant as metadata to add meaning to it. A good example would be a real document like a book - when stored in an XML file, a lot of the content would be the text of the book, and you would have some XML elements like <book>, <chapter>, <section>, <TOC>, etc. But for "data", a good example would be an invoice or a purchase order or a part record - while they do have text, it will be mainly in the form of structured fields (typically not too long, unlike a chapter or section in a book), which can again be stored in XML elements. And this is where the siblings and others are arguing about - which (XML or JSON) is a better format for what type - document or data.