0 a metal container in the street or other public place in which you can put letters for them to be collected and sent to someone else
1 a metal container in the street or other public place in which you can put letters to be mailed
2 → mailbox
If the card was one of teddy's favorites, the child was to post it into a postbox.
Every week we make our requests; they go into the postbox, and then disappear.
They put their name and address on the card, and put it in the postbox.
They simply acted as the postbox every time.
If they are going to be nothing but a postbox it can do nobody any good and can only lead to delay.
My children wished to post letters in the special postbox there, but we could find no stamps.
The postbox function is not confined to next steps agencies.
In fact, my local authority is rather like a postbox at the moment.