Pipe connection is a term used to describe the joining of two pipes together. The most common types of pipe connections are elbow (ELL) and TEE (TEE). An elbow connection is a curved piece of pipe that allows for a change in direction, while a TEE connection is a straight piece of pipe with a branch at a 90 degree angle. Both types of connections are used to join two pipes together, allowing for the flow of liquids or gases.