noun
Refers to a public collection box for outgoing mail, typically red in Japan. Synonymous with ポスト in everyday speech.
See also: ポスト
郵便差出箱に手紙を投函した。
I dropped the letter into the postbox.
Standard kanji spelling for a public postbox.
Variant with okurigana; less common but still seen.
More common in everyday conversation; 郵便差出箱 is a formal or official term.
Compound of 郵便 (postal), 差出 (sending out), and 箱 (box).