The term "spare part" refers to a component or piece that is kept in reserve for use in repairing, maintaining or replacing a machine or system. These components are typically designed and manufactured specifically for a particular model or brand of equipment, and can be used to fix or upgrade the device without having to replace it entirely. Spare parts may include anything from small screws and bolts to larger components such as motors, gears, or electronic modules. Having spare parts on hand is important because it allows for quick repairs and minimizes downtime when a machine breaks down or malfunctions.