5 strokes
container, open mouth
concave, hollow, sunken
Jōyō kanji, taught in junior high
JLPT level N1
2206 of 2500 most used kanji in newspapers


Stroke order

On reading compounds

  • 凹 【オウ】 concave, hollow, sunken
  • 凹凸 【オウトツ】 unevenness, bumpiness, roughness, ruggedness, imbalance, inequality, unevenness, disparity
  • 肋凹 【ロクオウ】 costal fovea

Kun reading compounds

  • 窪む 【くぼむ】 to cave in, to become depressed, to sink
  • 凹む 【へこむ】 to be dented, to be indented, to yield, to give, to sink, to collapse, to cave in, to be beaten, to be overwhelmed, to yield, to give in, to give up, to be disheartened, to feel down, to feel depressed, to suffer a loss, to lose
  • 発達凸凹 【はったつでこぼこ】 developmental irregularities, developmental disorder, neurodiversity
  • 穴ぼこ 【あなぼこ】 hole, hollow, pothole (road, pavement, etc.)


Mandarin Chinese (pinyin):
ao1, wa1


  • hueco
  • cóncavo
  • hundido


  • côncavo
  • concavidade
  • afundado


  • concave
  • creux
  • dépression
1032 A Guide To Remembering Japanese Characters (Kenneth G. Henshall)
1920 A New Dictionary of Kanji Usage
664 Classic Nelson (Andrew Nelson)
1883 Essential Kanji (P.G. O’Neill)
1087 Japanese Kanji Flashcards (Max Hodges and Tomoko Okazaki)
1893 Kanji and Kana (Spahn and Hadamitzky)
2069 Kanji and Kana, 2nd Edition (Spahn and Hadamitzky)
1922 Kanji in Context (Nishiguchi and Kono)
173 Kodansha Compact Kanji Guide
4294 Kodansha Kanji Dictionary (Jack Halpern)
2170 Kodansha Kanji Learner’s Dictionary (Jack Halpern)
2924 Kodansha Kanji Learner’s Dictionary, 2nd Edition (Jack Halpern)
33 Les Kanjis dans la tete (Yves Maniette)
1810 Morohashi
3482 New Japanese English Character Dictionary (Jack Halpern)
444 New Nelson (John Haig)
33 Remembering The Kanji (James Heisig)
33 Remembering The Kanji, 6th edition (James Heisig)
1039 Tuttle Kanji Cards (Alexander Kask)
3675 2001 Kanji
0a5.14 The Kanji Dictionary
4-5-1 SKIP code
4-6-1 SKIP code
4-4-1 SKIP code
7777.0 Four corner code
1-17-90 JIS X 0208-1997 kuten code
51f9 Unicode hex code