洞 (dòng) is a Chinese character meaning “cave”. It is written from 氵 (water (left-side form)) and 同 (same; together), side by side, and takes 9 strokes.
Build the character for “cave; hole”
Four steps: break it apart, build it, recall it, use it in a word.
StartLearn this character
Structure
氵 + 同
Left–right structure
Structure from: 说文解字「洞，疾流也。从水同聲」；IDS 拆分 ⿰氵同，并以 hanzi-writer-data 笔画核验：笔画 0–2 为「氵」三点，笔画 3–8 与「同」六笔逐笔对应（3+6=9画）
Memory aid
Water (氵) dripping on the same (同) spot year after year — until it hollows out a cave.
This is a memory aid, not the historical origin.
Stroke order
9 strokes
In real words
- 山洞shān dòngcave (in a mountain)洞 = dòng
- 洞穴dòng xuécave洞 = dòng
- 窑洞yáo dòngcave dwelling (dug into a loess hillside)洞 = dòng
Go deeper
All readings
cave; hole
cave; hole; cavity; to see through clearly
物体上穿通的孔；山中或地下的空穴。也表示透彻地看清。 — studyhanzi 编写
Words with this reading
- 山洞shān dòngcave (in a mountain)洞 = dòng
- 洞穴dòng xuécave洞 = dòng
- 窑洞yáo dòngcave dwelling (dug into a loess hillside)洞 = dòng
Stroke data: hanzi-writer-data (Arphic Public License) · licenses & attributions
Questions people ask about this character
What does 洞 mean?
洞 (dòng) means cave; hole; cavity; to see through clearly.
How do you pronounce 洞?
It is pronounced dòng.
What parts is 洞 made of?
氵 (water (left-side form)) and 同 (same; together), side by side. The recorded source is: 说文解字「洞，疾流也。从水同聲」；IDS 拆分 ⿰氵同，并以 hanzi-writer-data 笔画核验：笔画 0–2 为「氵」三点，笔画 3–8 与「同」六笔逐笔对应（3+6=9画）. Components are the building blocks of the shape; the radical used for dictionary lookup is a separate thing.
How many strokes does 洞 have?
9. You can watch the stroke order on this page, or trace it yourself.
What is the radical of 洞?
氵. 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 洞?
Common ones are 山洞 and 洞穴. The reading of 洞 is not the same in every word, so each word on this page shows which reading applies.