一、函(hán),原指信封。如吴质《答东阿王书》:“发函伸纸。”(打开信封,拿出信纸。)《三国志·魏书·刘晔传》注引《傅子》,有“每有疑事,辄以函问晔”(每次碰上疑难的事情,总是通过信件来请教刘晔)句。这里的“函”则是指信件。现在,我们把函作为书信的代名词,常被广泛使用。便信可称“便函”,密信则称“密函”,公文就是“公函”,等等。 First, the letter (hán) originally refers to the envelope. For example, “Qiang Dong’s Book of Kings in the East”: “Send a letter to the paper.” (Open the envelope and take out the stationery.) “The Book of the Three Kingdoms Wei Shu and the biography of Liu Wei” are quoted as “Fu Zi” and “If there is any doubt, Asked by letter, “(everything that comes up with a difficult matter, always ask Liu Tong by letter). The ”letter“ here refers to the letter. Nowadays, we use letters as a synonym for letters and are often used extensively. The confession can be called a ”memo“, the secret letter is called a ”secret letter,“ and the official document is ”an official letter," and so on.