Shelf-wear
From Brickwiki
Shelf-wear is a term to describe the damage done to a LEGO set as it sits on the shelf of a retailer and gets handled and moved around.
When purchased and listed by resellers on sites such as Bricklink or eBay the degree of shelf-wear determines if a set can be sold as New in sealed box (NISB) or Mint in sealed box (MISB). These terms are very important to collectors and can result in disputes if scuffs, scratches and other cosmetic damage is not accounted for in the sale listing.