An automotive package is a set of optional automobile features that are included in a bundle that is installed at the factory (this is, they are added to the standard features).
In some cases, elements from multiple packages may be combined to create a model level. Such mixing of packages is common in imported vehicles, where it is relatively difficult to produce specific combinations to a customer's order owing to relatively long shipping times. For example, a high level luxury package may include a premium sound system, projector headlights, a navigation system, and side curtain air bags,and heat seats with this particular combination sold only as a high level model, with some designation such as "DX" (delux), "LE" (luxury edition), "SE" (special edition) and "ES" (electric standard).
Package is also an industry term for the job of defining the basic architecture of the vehicle. This includes figuring out how to fit the engine, transmission and passengers into the car, and what the ground clearance will be.