Grade

Rank is rather similar to Star rarity; It's an indicator of how good, or how expensive a piece of Equipment is. More importantly, it imposes an indirect usability requirement on the item, based on a user's current Class and Class level. Currently, not too much is known about this though. However, it is known that some classes are incapable of getting even 'rank C' in certain categories (such as Hunters and Rangers for Rods), they may never be able to use such items at all.