Parts

Parts are discrete elements that combine to form a larger object or system. Each part has a defined function and specific interfaces, and it contributes to the performance, structure, or behavior of the whole. In engineering and manufacturing, parts range from fasteners and gaskets to gears, bearings, housings, and electronic modules. Some parts are standard and off-the-shelf, designed for broad compatibility, while others are custom-made for a particular design.

Parts are documented and controlled through drawings, specifications, and bills of materials (BOMs). Key details include dimensions, tolerances, materials, finishes, and mounting interfaces. Interchangeability and standardization are important concepts, enabling parts to be replaced or upgraded without redesigning the whole system. Standardized fasteners, connectors, and interfaces—across industries such as automotive, aerospace, and electronics—facilitate sourcing, maintenance, and repair.

Lifecycle management of parts covers procurement, inventory, maintenance planning, and obsolescence. Effective parts management reduces downtime, lowers total cost of ownership, and extends product life. In software and systems contexts, "parts" can also refer to modular components or subsystems, reflecting the same principle of composability. In broader usage, the term denotes any constituent element that, together with others, forms a whole.