United States Postal Service; USPS
Official name of the U.S. postal service; used in formal or news contexts.
The United States Postal Service operates the postal business in the United States.
郵便局 is a general post office, while 米国郵政公社 specifically refers to the USPS organization.
Compound of 米国 (United States) + 郵政 (postal administration) + 公社 (public corporation).