Pickled onions are a food item consisting of onions (cultivars of Allium cepa) pickled in a solution of vinegar and salt, often with other preservatives and flavourings. There is a variety of small white pickled onions known as 'silverskin' onions; due to imperfections they are pickled instead of being wasted. They are frequently used as an essential component of the Martini cocktail variant known as a Gibson.