| 1661 | A Guide To Remembering Japanese Characters (Kenneth G. Henshall) |
| 1756 | A New Dictionary of Kanji Usage |
| 2546 | Classic Nelson (Andrew Nelson) |
| 1468 | Japanese Kanji Flashcards (Max Hodges and Tomoko Okazaki) |
| 821 | Japanese Names (P.G. O’Neill) |
| 1301 | Kanji and Kana (Spahn and Hadamitzky) |
| 1380 | Kanji and Kana, 2nd Edition (Spahn and Hadamitzky) |
| 1844 | Kanji in Context (Nishiguchi and Kono) |
| 1191 | Kodansha Compact Kanji Guide |
| 455 | Kodansha Kanji Dictionary (Jack Halpern) |
| 280 | Kodansha Kanji Learner’s Dictionary (Jack Halpern) |
| 340 | Kodansha Kanji Learner’s Dictionary, 2nd Edition (Jack Halpern) |
| 183 | Les Kanjis dans la tete (Yves Maniette) |
| 17386 | Morohashi |
| 380 | New Japanese English Character Dictionary (Jack Halpern) |
| 3125 | New Nelson (John Haig) |
| 181 | Remembering The Kanji (James Heisig) |
| 193 | Remembering The Kanji, 6th edition (James Heisig) |
| 1276 | Tuttle Kanji Cards (Alexander Kask) |
Jōyō kanji, taught in junior high
JLPT level N1
1618 of 2500 most used kanji in newspapers
Stroke order
On reading compounds
- 洞 【ドウ】 sinus, cavity, antrum, neighborhood (administrative division in North Korea)
- 洞察 【ドウサツ】 discernment, insight
- 空洞 【クウドウ】 cavity, hollow, cave, cavern, hollow
- 風洞 【フウドウ】 wind tunnel
Kun reading compounds
- 洞 【ほら】 hollow, cavity, hole, cave
- 洞穴 【ほらあな】 cave, cavern, den, grotto
Readings
- Japanese names:
- とう
- Korean:
- dong, tong
Spanish
- cavidad
- hueco
- excavación
- prever
Portuguese
- gruta
- caverna
- escavação
French
- antre
- grotte
- excavation
| 349 | 2001 Kanji |
| 3a6.25 | The Kanji Dictionary |
| 1-3-6 | SKIP code |
| 3712.0 | Four corner code |
| 1-38-22 | JIS X 0208-1997 kuten code |
| 6d1e | Unicode hex code |
Jōyō kanji, taught in grade 6
JLPT level N1
1366 of 2500 most used kanji in newspapers
Stroke order
On reading compounds
- 穴 【ケツ】 ass, arse, buttocks, rear, end, acupuncture point, hole, notch
- 穴隙 【ケツゲキ】 crevice, aperture
- 横穴 【ヨコアナ】 cave, tunnel, tunnel tomb (Kofun period)
- 経穴 【ケイケツ】 acupuncture point
Kun reading compounds
- 穴 【あな】 hole, opening, orifice, perforation, pit, hollow, cavity, hole (e.g. in the ground), burrow, den, lair, holt, hole, deficit, shortage, (financial) hole, loss, gap (left by a missing employee, team member, etc.), vacancy, opening, flaw, fault, defect, weak point, hole (in a theory, plan, etc.), loophole, good place not many people know about, well-kept secret, upset victory (with a large payoff), long shot, dark horse, (partitioned) box (type of floor seating in a traditional Japanese theatre), hiding place, hideout
- 穴埋め 【あなうめ】 filling (up) a hole, filling in (for a gap, vacancy, etc.), stopgap, filler (e.g. article), making up (for a loss, damage, etc.), covering (a deficit), compensation, cloze deletion (test format)
- 風穴 【かざあな】 air hole, windhole, ventilator
- 横穴 【よこあな】 cave, tunnel, tunnel tomb (Kofun period)
Readings
- Japanese names:
- けな、 しし、 な
- Korean:
- hyeol
Spanish
- agujero
- hueco
- cueva
- lugar poco conocido
- lugar escondido
Portuguese
- buraco
- orifício
- brecha
- caverna
- gruta
French
- trou
- orifice
- fente
- grotte
- tanière
| 860 | A Guide To Reading and Writing Japanese 3rd edition (Henshall, Seeley and De Groot) |
| 849 | A Guide To Remembering Japanese Characters (Kenneth G. Henshall) |
| 1201 | A New Dictionary of Kanji Usage |
| 3313 | Classic Nelson (Andrew Nelson) |
| 984 | Essential Kanji (P.G. O’Neill) |
| 1595 | Japanese Kanji Flashcards (Max Hodges and Tomoko Okazaki) |
| 158 | Japanese Names (P.G. O’Neill) |
| 899 | Kanji and Kana (Spahn and Hadamitzky) |
| 921 | Kanji and Kana, 2nd Edition (Spahn and Hadamitzky) |
| 1122 | Kanji in Context (Nishiguchi and Kono) |
| 1450 | Kodansha Compact Kanji Guide |
| 2682 | Kodansha Kanji Dictionary (Jack Halpern) |
| 1366 | Kodansha Kanji Learner’s Dictionary (Jack Halpern) |
| 1852 | Kodansha Kanji Learner’s Dictionary, 2nd Edition (Jack Halpern) |
| 1326 | Les Kanjis dans la tete (Yves Maniette) |
| 25406 | Morohashi |
| 2159 | New Japanese English Character Dictionary (Jack Halpern) |
| 4187 | New Nelson (John Haig) |
| 1316 | Remembering The Kanji (James Heisig) |
| 1413 | Remembering The Kanji, 6th edition (James Heisig) |
| 834 | Tuttle Kanji Cards (Alexander Kask) |
| 762 | 2001 Kanji |
| 3m2.2 | The Kanji Dictionary |
| 2-3-2 | SKIP code |
| 3080.2 | Four corner code |
| 1-23-74 | JIS X 0208-1997 kuten code |
| 7a74 | Unicode hex code |