What is fitting?

In engineering and manufacturing, "fitting" generally refers to parts used to connect or terminate sections of pipes, tubes, or hoses in plumbing and piping systems. Fittings are used to join multiple pipes or tubes together, adapt to different sizes, shapes, or materials, and control the flow of fluids or gases. They come in various materials (e.g., metal, plastic) and types (e.g., elbows, tees, couplings, reducers, valves). "Fitting" can also broadly refer to the process of assembling or adjusting components to ensure proper function or alignment in mechanical systems. In statistics, fitting refers to the process of finding the curve that best matches a set of data points.