What is the name of the small metal or plastic spool beneath the needle in a sewing machine?

The small metal or plastic spool beneath the needle in a sewing machine is called a bobbin. This component is crucial because it holds the thread that gets fed into the stitching process, allowing the machine to create stitches by intertwining the top and bottom threads. The bobbin works in conjunction with the needle, providing the lower thread that interacts with the upper thread to form a seam.

While the other terms are related to sewing, they serve different purposes. A reel generally refers to a larger device used to hold or dispense thread, and a spool is a broader term that can describe both the bobbin and any larger container of thread or yarn. The spindle is the part of the sewing machine that holds the spool of thread on top, allowing it to unwind as the machine is operated. Therefore, "bobbin" specifically identifies the component that plays a direct role in thread management beneath the needle.