Noun: 1) An item that belongs somewhere or does something but you can't remember where or what it does. 2) A product that has a purpose but is in the wrong spot. 3) A thing that is useful in only one capacity but does not belong in the context.
I found this tooage in the glove box of my car and I know it operates something? (unlocks the spare wheel, removes the roof racks etc.) 2. An item that has to go "to" the correct spot to become useful 3) When you find a needle in a haystack (What the hell is this doing here?)