what does diplomatic pouch mean?

DIPLOMATIC POUCH as NOUN

Meaning
- a mail pouch that is sealed shut and that is used to carry communications between a legation and its home office
Hypernyms(s) diplomatic pouch is a kind of… Example: animal is a hypernym of mammal, plant is a hypernym of flower
- mailbag (what does mailbag mean?)
- mail pouch (what does mail pouch mean?)