Auto part or any part number (often abbreviated PN, P/N, part no., or part #) is an identifier of a particular part design used in a particular industry. Its purpose is to simplify reference to that part. A part number unambiguously identifies a part design within a single corporation, and sometimes across several corporations. As a part number is an identifier of a part design (independent of its instantiations), a serial number is a unique identifier of a particular instantiation of that part design. In other words, a part number identifies any particular (physical) part as being made to that one unique design; a serial number, when used, identifies a particular (physical) part (one physical instance), as differentiated from the next unit that was stamped, machined, or extruded right after it. source: Wikipedia
For example, when specifying a auto part COVER PLATE, it is easier to refer to auto part number "B25N59A" than saying "COVER PLATE / FOR CORED HOLE OF OIL PUMP DRIVE, LATERAL Chasis, Car". In this example, "B25N59A" is the auto part number, and it may be prefixed in database fields as "B25.N5-9a" or "MB B25.N5-9a".
For your convenient use, all auto part numbers are grouped into part number designation, Market, model designations, catalog, what models use the part. Also they are linked to necessary schema to see how it is located.
Almost every auto part number is written on the front of the part, it consist of Arabic numbers and letters. It is common for part numbers (as well as serial numbers or other information) to be marked on the part in ways that facilitate machine-readability, such as barcodes or QR codes. Today's advanced state of optical character recognition (OCR) technology also means that machines can often read the human-readable format of Arabic numerals and Latin script.