The term 'Gibson Garnishes' refers to two types of garnishes used in cocktails. The first is onions, which are a 6-letter word. Onions are a vegetable that are often used as a garnish in cocktails, adding flavor and texture. The second is pearl onions, which are 11 letters long. Pearl onions are small, round onions that are often pickled and used as a garnish in cocktails, adding a unique flavor and texture.