Definitions
There are 2 meanings of the phrase
Box Number.
Box Number - as a noun
The number of a letter box at the post office where mail is collected
Synonyms (Exact Relations)
A mailing address to which answers to a newspaper ad can be sent
Example Sentences
"Please enter your box number when filling out the form."
"I keep all my important documents in a locked box number 123."
"The package was delivered to box number 456 at the post office."
"To send a letter to me, use box number 789."
"He provided a false box number to avoid being traced."