What Are The Different Types Of Plumbing Connections?

Pipe fittings dimensions are important and there are sizing standards to follow. While most have openings of the same size on each end, some fittings are designed with different-sized openings and serve as the transition from one size pipe to another.
A wide variety of fittings are used in plumbing. Examples: brass, copper, CPVC, flexible, PVDF, cast iron, black, ABS, nylon, PVC and galvanized steel. There are no normal connectors and thread types in plumbing. Plumbing threads come in different sizes and different styles.