A universal joint (U-joint) is a mechanical connection that allows for the transmission of torque and rotational motion between two shafts that are not aligned. It consists of a pair of hinges connected by a cross-shaped pivot, enabling the shafts to flexibly transmit power at an angle. Universal joints are widely used in applications such as automotive drivetrains, industrial machinery, and agricultural equipment. They are valued for their simplicity, durability, and ability to accommodate angular misalignment, making them essential in systems with variable or offset shaft angles.