Chocolate: A food or flavoring made from the seeds of the cacao or chocolate tree. Chocolate (especially dark chocolate) is rich in flavonoids, compounds that act as antioxidants. Flavonoids may also lower blood pressure and improve blood flow, by regulating the synthesis of nitric oxide, which dilates blood vessels. Flavonoids, like aspirin, help keep platelets from aggregating on vessel walls. Thus, chocolate may have health benefits, provided it is consumed in moderation.