noun (n)

• a numbered compartment in a post office where mail is put to be called for(noun.artifact)

  Synonym:
  call box, po box, pob, post-office box
  

  source: wordnet30
• public box for deposit of mail(noun.artifact)

  Synonym:
  mailbox, postbox
  

  source: wordnet30
• a private box for delivery of mail(noun.artifact)

  Synonym:
  mailbox
  

  source: wordnet30