函 (hán) is a Chinese character meaning “letter”. It is written from 凵 (open box) and ㇇ (horizontal-turning stroke) and 氺 (water (form used at the bottom of a character)), one enclosing the other, and takes 8 strokes.
Build the character for “letter; envelope”
Four steps: break it apart, build it, recall it, use it in a word.
StartLearn this character
Structure
凵 + ㇇ + 氺
Enclosing structure
- 凵 open box · kǎn unknown
- ㇇ horizontal-turning stroke unknown
- 氺 water (form used at the bottom of a character) · shuǐ unknown
Structure from: hanzi-writer-data 笔画核验（现代字形拆分：1 + 5 + 2 = 8 笔，第 2–6 笔与「氺」逐笔同形）
Memory aid
A hooked stroke (㇇) folds over a spray of water (氺), and the open frame (凵) closes around the whole thing — something wrapped up and sealed, the way a letter goes into its envelope.
This is a memory aid, not the historical origin.
Stroke order
8 strokes
In real words
- 信函xìn hánletter; correspondence函 = hán
- 函数hán shùfunction (in mathematics)函 = hán
Go deeper
All readings
letter; envelope
letter; official correspondence; an envelope or case that holds something; (formal) to contain
信件；书信。也指封套，书面语中还有「包含」的意思。 — studyhanzi 编写
Words with this reading
- 信函xìn hánletter; correspondence函 = hán
- 函数hán shùfunction (in mathematics)函 = hán
Stroke data: hanzi-writer-data (Arphic Public License) · licenses & attributions
Questions people ask about this character
What does 函 mean?
函 (hán) means letter; official correspondence; an envelope or case that holds something; (formal) to contain.
How do you pronounce 函?
It is pronounced hán.
What parts is 函 made of?
凵 (open box) and ㇇ (horizontal-turning stroke) and 氺 (water (form used at the bottom of a character)), one enclosing the other. The recorded source is: hanzi-writer-data 笔画核验（现代字形拆分：1 + 5 + 2 = 8 笔，第 2–6 笔与「氺」逐笔同形）. Components are the building blocks of the shape; the radical used for dictionary lookup is a separate thing.
How many strokes does 函 have?
8. You can watch the stroke order on this page, or trace it yourself.
What is the radical of 函?
凵. The radical is how the character is filed in a dictionary — it is not the whole story of how the character is built.
What words use 函?
Common ones are 信函 and 函数. The reading of 函 is not the same in every word, so each word on this page shows which reading applies.