Pipe joint is a term used to describe the connection between two pipes. The most common types of pipe joints are ELBOW, ELL, TEE, and wye. An ELBOW joint is a curved piece of pipe that connects two straight sections of pipe at an angle. An ELL joint is a short piece of pipe that connects two straight sections of pipe at a 90 degree angle. A TEE joint is a T-shaped piece of pipe that connects three straight sections of pipe. A wye joint is a Y-shaped piece of pipe that connects three straight sections of pipe at an angle.