Cos lettuce, also known as romaine lettuce, is a popular salad green with crisp, elongated leaves and a slightly bitter flavor. It is known for its crunchy texture and refreshing taste, making it a staple ingredient in many salads. Cos lettuce is often used as a base for salads, such as Caesar salads, and can be combined with other vegetables, fruits, or proteins to create a delicious and nutritious meal. Its sturdy leaves also make it suitable for use as a wrap or a substitute for bread in sandwiches and burgers.