Green olives are famous for being the garnish of traditional Martinis. It is recommended to serve olives without fillings such as red pepper, onion or almonds. Olives are served skewered on a pick and placed in the drink. Use black olives only when drink specifically calls to use it.
It is a common term for a decoration made with olives or onion in dirty martinis and cosmopolitans.
It can also be applied for maraschino cherries, berries or small vegetables skewed on toothpick, stirrer or swizzle.