SOME PLUMBING JOINTS is a term used to describe two types of plumbing fittings. ELLS and Tees are both four letter words that refer to specific types of plumbing joints. ELLS are L-shaped fittings that are used to change the direction of a pipe, while Tees are T-shaped fittings that are used to connect three pipes together. Both ELLS and Tees are commonly used in plumbing systems to join pipes together.