usps priority mail meaning refers to a service offered by the United States Postal Service that provides expedited shipping within the U.S. with delivery typically within 1-3 business days. USPS Priority Mail includes tracking and insurance up to $50. It is an affordable option for sending parcels and envelopes that need quicker delivery than First-Class Mail but without the high cost of services like Express Mail. Priority Mail offers flat-rate boxes, making it easier to ship items of different weights for the same price, provided they fit in the specified boxes.