Collard greens are a type of green (duh), leafy plant (vegetable) that is used in southern cooking, usually simmered in a pot with chopped onion, hamhock, and various seasonings. The longer you cook them, the more tender and flavor-filled they become. I recommend trying them at least once...they are delicious when cooked right! You can eat them with just about anything, fried catfish, ham, turkey....and anything else you can imagine.