洞 means “cave, hollow”

どう · dou

Also: den, excavation

Kun'yomi (Japanese reading)

ほら

On'yomi (Chinese reading)

ドウ

JLPT N1 · Taught in secondary school · 9 strokes

The story

Water (氵) beside 同, the same: picture water running the same path for ages until the rock hollows into a cave. 洞窟 is a cave, 鍾乳洞 a limestone cave hung with stone icicles, and 洞察 is insight, seeing into the hollow of things.

Used in 洞窟 (doukutsu, cave), 空洞 (kuudou, hollow/cavity), and 洞察 (dousatsu, insight)

More from Peaks & Caves

• 峡 gorge
• 峰 peak
• 峠 mountain pass
• 坑 pit
• 麓 foot of a mountain
• 窟 cavern
• 塚 mound
• 岳 high mountain
• 丘 hill

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Readings from KANJIDIC2, © EDRDG, CC BY-SA.