A prearranged place for a swap or drop of information or goods. Particularly common usage with Spies or drug dealers.
"The Microfilm was left at the dead letterbox as arranged. We can now release the prisoner."
by Andy 696969 October 17, 2006
1 more definition
I can't deliever this letter so stick it in the dead letterbox.
by mspenguin November 01, 2006