"Refurbished"?

I guess we all know what a "new" component is, what a "demo" component is and what a "used" component is. We can quibble on the "box opened just for inspection" representation as somewhat fudging the concept of "new" and feel much better thinking that an unopened box really means it certifies the product within as really, really "new". My question then is : what is actually a "refurbished" product? Is it the same as a "B" product? Is there anything actually done to the unit to qualify it as "refurbished" aside from taking off the fingerprints and packing it neatly in the original shipping materials? Does a component returned by a consumer for some malfunction that is then repaired qualify as "refurbished". Is "refurbished" a cleaned up demo sent back to the manufacturer when a line or specific product in a line is passed over by the buying public or being replaced by a manufacturer to be liquidated by a central agent?. In short, are we, yet again, dealing with fuzzy definitions? Oh BTW what would the range of % discount be on demo units and refurbished units, if one accepts all the problems with generalizations?