Declaration by Foreign Shipper

The U.S. Customs Service defines this term as a statement by the shipper in
the foreign country attesting to certain facts. For example, articles
shipped from the United States to an insular possession and then returned
must be accompanied by a declaration by the shipper in the insular
possession, indicating that, to the best of his or her knowledge, the
articles were exported directly from the United States to the insular
possession and remained there until the moment of their return to the
United States. (see 19 CFR 4.60 and 4.61 on U.S. clearance of vessels
bound for a foreign port or ports.)