The term 'purple vegetable' can refer to two different vegetables: radicchio and BEET. Radicchio is a leafy vegetable that is part of the chicory family, and it has a bitter flavor. It is usually eaten raw in salads or cooked in dishes. BEET is a root vegetable that is often boiled or roasted. It has a sweet taste and is often used in salads or as a side dish. Both radicchio and BEET are purple in color and are popular vegetables in many cuisines.