Translation guide
A letter box is a container for receiving incoming mail, typically at a home or office. In Japanese, the most common term is 郵便受け (yūbin'uke), but other words exist depending on context, such as public postboxes or slots in doors.
letter box (home)
letter box (public)
A box or slot for receiving delivered mail at a residence or office.
The standard term for a mailbox attached to a house or building where mail is delivered.
Please check the letter box.
Commonly used for both home mailboxes and public postboxes. Context usually clarifies which is meant.
Less common; can refer to a mailbox but often sounds slightly more formal or old-fashioned.
A red or blue box on the street where you deposit outgoing mail.
A slot in a door or wall for mail delivery, common in apartments.
郵便受け (yūbin'uke) is specifically for receiving mail at a residence. ポスト (posuto) can mean either a home mailbox or a public postbox, but context usually makes it clear. When in doubt, use 郵便受け for your own mailbox and ポスト for the red box on the street.
I installed a new letter box.
There was a letter in the letter box.
Open the letter box.
More explicit than ポスト, emphasizing it's for mail. Used when distinction is needed.
Where is the letter box?
The letter box slot is clogged.