sanduče

1. small box; crate
   Kupili smo sanduče jabuka na pijaci. — We bought a crate of apples at the market.
2. (for letters) mailbox; letterbox
   U poštanskom sandučetu su bili samo računi. — There were only bills in the mailbox.
   Proveri sanduče kad budeš ulazio u zgradu. — Check the mailbox when you come into the building.
3. (of email) email mailbox; mail folder
   Elektronsko sanduče mi je puno. — My email mailbox is full.
   Mejl mi je završio u spam sandučetu. — The email ended up in my spam folder.

In the sense of "mailbox" it often comes with the adjective: poštansko sanduče.