postroom
nounUK /ˈpəʊst.ruːm/
US /ˈpoʊst.ruːm/
A room where letters and packages are sorted and sent out.
She dropped the parcel off at the postroom before lunch.
OTHER MEANINGS
2. A department in a company that handles incoming and outgoing mail.
Contact the postroom if your package hasn't arrived.
3. A small office in a building where mail is collected and distributed.
The postroom is on the ground floor next to reception.
4. The place where mail is prepared for dispatch.
All letters go through the postroom before being sent.