Which type of plumbing fitting is specifically designed to connect three pipes?

The type of plumbing fitting specifically designed to connect three pipes is a tee. This fitting has three openings, allowing for two pipes to enter into one side and one pipe to connect to the other side, enabling the flow of liquid or gas from one main line into a branch line. The tee is commonly used in various plumbing configurations to create branch connections from a main pipeline.

In contrast, the reducer is used to connect two pipes of different diameters, facilitating a smooth transition in pipe size rather than connecting three pipes. An elbow is designed to change the direction of flow between two pipes, typically at a 90-degree or 45-degree angle, but does not accommodate a third connection. A bend serves a similar function as the elbow but has a wider radius and is primarily used to gradually change the direction of a single pipe. Thus, tees uniquely fulfill the requirement of connecting three pipes in plumbing systems.