postbox
noun(also letter box)
(both British English) (North American English mailbox)
a public box, for example in the street, that you put letters into when you send them 邮筒；邮箱 
The postman put a bundle of letters through the letter box. 邮递员把一捆信放入信箱。 There's a letter box on the corner of the street. 街角那儿有一个邮筒。
