mail drop
noun
1
- N. Amer. a receptacle for mail, especially one in which mail is kept until the addressee collects it〈北美〉（尤指保存邮件直至收件人领取的）邮箱, 信箱。
2
- Brit. a delivery of mail, advertising leaflets, or other material〈英〉（邮件、宣传品等）投递。