凹 means “concave, dent”

おう · ou

Also: hollow, sunken

Kun'yomi (Japanese reading)

くぼむ, へこむ, ぼこ

On'yomi (Chinese reading)

オウ

JLPT N1 · Taught in secondary school · 5 strokes

The story

The twin of 凸: a block with a notch sunk into its top. 凹 is concave: a 凹レンズ spreads light, 凹凸 is unevenness, and 凹む, hekomu, is to be dented, said of a car door, or of a person after bad news.

Used in 凹む (hekomu, to be dented/to feel down), 凸凹 (dekoboko, bumpy/uneven), and 凹凸 (outotsu, unevenness)

More from Shapes & Angles

• 弧 arc
• 隙 gap
• 環 ring
• 枠 frame
• 端 edge
• 距 distance
• 圏 sphere
• 縦 vertical
• 緯 latitude
• 径 diameter
• 斜 diagonal
• 傍 beside

Learn 凹 and more kanji free on Fuji Learning · All kanji

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