To garnish means to adorn a dish with a small amount of some ingredient as a decoration or to add a bit of flavor. When garnish is used as a noun, the ingredient itself is referred to as the garnish.
Parsley or some other mild herbs are often used as garnishes for main entrees, while sliced fruit is a common garnish for desserts.
Garnish
A serving of rice with a garnish of herbs, nuts, and dried fruit.