A parallel pipe nipple is a type of pipe fitting used to connect two pipes or fittings of the same diameter in a straight line. It consists of a short length of pipe with threads on both ends to allow for easy attachment to other pipes or fittings.

The term “parallel” refers to the fact that the threads on the nipple run parallel to each other, as opposed to tapered pipe threads which converge to a point. This design allows for a more secure and leak-resistant connection, especially in applications where high pressure or temperature is involved. Parallel pipe nipples are commonly used in plumbing, HVAC, and industrial piping systems.