A joint is a connection between two or more bones in the body, allowing for movement and flexibility. Joints can be classified into different types based on their structure and function, such as hinge joints, which allow movement in one direction, and ball-and-socket joints, which enable a wider range of motion. Common examples of joints include the knee, elbow, and shoulder. Joints are held together by ligaments, which are strong bands of tissue that provide stability. The surfaces of the bones at a joint are often covered with cartilage, a smooth tissue that reduces friction and absorbs shock during movement. Proper joint health is essential for overall mobility and can be affected by factors like age, injury, and arthritis.