1. The engine number is called the VIN, or Vehicle Identification Number, a unique code assigned to each vehicle by the manufacturer for identification purposes.
2. The VIN is a 17-digit alphanumeric code, also known as the 17-digit identification code, chassis number, or 17-digit number.
3. Through permutations and combinations, the VIN ensures that no two vehicles of the same model will have the same VIN within 30 years, providing unique identification for each vehicle; therefore, it can also be referred to as a "vehicle ID card."