Plumbing joint is a term used to describe the connection between two pipes or tubes. The most common types of plumbing joints are the TEE and ELL. A TEE joint is a type of pipe fitting that has three openings, allowing two pipes to be connected at a 90 degree angle. An ELL joint is a type of pipe fitting that has two openings, allowing two pipes to be connected at an angle other than 90 degrees. Both TEE and ELL joints are commonly used in plumbing systems to join pipes and create a secure connection.