A parcel. The addressed container of whatever it is you're shipping, whether a box, large envelope, styrofoam cooler held together with yards of duct tape, etc.
UPS and other shippers put a barcode and tracking number on the label of the package. The package is scanned and the information put into a computer at every point along the way, so that it's possible for the customer, logging in on his home computer, to see its progress from origin to destination and know exactly when it will be delivered.
I think that is VERY cool.