Wiktionary
n. (context US English) A diplomatic bag.
WordNet
n. a mail pouch that is sealed shut and that is used to carry communications between a legation and its home office
Usage examples of "diplomatic pouch".
Most of his previous flights had been to deliver or pick up a diplomatic pouch or other correspondence between the Embassy in Buenos Aires and the German Embassy here.
He may be, too, interested in the contents of the diplomatic pouch.
Bretti saw the diplomatic pouch container holding the Penning trap near the central cylinder.
It arrived by cable, alerting him to an Eyes-Only-Chairman message en route in the diplomatic pouch.
The diplomatic pouch had the window seat, with Giannini in the middle.
He found the heavy diplomatic pouch in which those important documents were carried.
The Kingdom rider was exhausted as he had been ordered not to surrender the contents of the diplomatic pouch to any but Earl James, Baron Locklear, or Prince Erland.