凹 (āo) is a Chinese character meaning “concave”. It is written from ㇑ (vertical stroke) and ㇅ (horizontal-turn-turn stroke) and ㇑ (vertical stroke) and ㇕ (horizontal-turning stroke) and ㇐ (horizontal stroke), and takes 5 strokes.
Build the character for “concave; sunken”
Four steps: break it apart, build it, recall it, use it in a word.
StartLearn this character
Structure
㇑ + ㇅ + ㇑ + ㇕ + ㇐
Overlapping structure
- ㇑ vertical stroke unknown
- ㇅ horizontal-turn-turn stroke unknown
- ㇑ vertical stroke unknown
- ㇕ horizontal-turning stroke unknown
- ㇐ horizontal stroke unknown
Structure from: Unicode U+51F9 与 hanzi-writer-data 2.0.1 现代字形观察（第 1 笔竖为左外壁、第 2 笔横折折折出上方缺口的左半、第 3 笔短竖为缺口右壁、第 4 笔横折包住右外侧、第 5 笔长横封底）
Memory aid
The left wall (㇑) drops straight down. A folding stroke (㇅) steps in and cuts a notch out of the top, and a short vertical (㇑) closes the far side of that notch. The right wall (㇕) comes down outside it, and one long horizontal (㇐) seals the bottom. A shape with a bite taken out of its top: it caves in.
This is a memory aid, not the historical origin.
Stroke order
5 strokes
In real words
- 凹凸āo tūuneven; bumpy凹 = āo
- 凹陷āo xiànto cave in; to sink; a depression凹 = āo
Go deeper
All readings
concave; sunken
concave; hollow; sunken; dented in
比周围低下去的部分；向里洼进去，跟「凸」相对。 — studyhanzi 编写
Words with this reading
- 凹凸āo tūuneven; bumpy凹 = āo
- 凹陷āo xiànto cave in; to sink; a depression凹 = āo
Stroke data: hanzi-writer-data (Arphic Public License) · licenses & attributions
Questions people ask about this character
What does 凹 mean?
凹 (āo) means concave; hollow; sunken; dented in.
How do you pronounce 凹?
It is pronounced āo.
What parts is 凹 made of?
㇑ (vertical stroke) and ㇅ (horizontal-turn-turn stroke) and ㇑ (vertical stroke) and ㇕ (horizontal-turning stroke) and ㇐ (horizontal stroke). The recorded source is: Unicode U+51F9 与 hanzi-writer-data 2.0.1 现代字形观察（第 1 笔竖为左外壁、第 2 笔横折折折出上方缺口的左半、第 3 笔短竖为缺口右壁、第 4 笔横折包住右外侧、第 5 笔长横封底）. Components are the building blocks of the shape; the radical used for dictionary lookup is a separate thing.
How many strokes does 凹 have?
5. You can watch the stroke order on this page, or trace it yourself.
What is the radical of 凹?
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 凹?
Common ones are 凹凸 and 凹陷. The reading of 凹 is not the same in every word, so each word on this page shows which reading applies.