Definition of mailboxes:
(n) :
(chiefly US) A box into which mail is placed.
(n) :
A delivery point for mail, a box, compartment or slot for this purpose.
(n) :
A collection point for mail intended for onward delivery, a secure box or receptacle for this purpose.
(n) :
(computing) A folder or account for the storage of email; an electronic inbox or mailstore.