| 洞 | dòng | cave; hole; zero (unambiguous spoken form when spelling out numbers); CL:个 |
| 张之洞 | Zhāng Zhī dòng | Zhang Zhidong (1837-1909), prominent politician in late Qing |
| 空洞 | kōng dòng | cavity; empty; vacuous |
| 洞口 | dòng kǒu | cave mouth; tunnel entrance; Dongkou county in Shaoyang 邵阳, Hunan |
| 漏洞 | lòu dòng | leak; hole; gap; loophole |
| 窑洞 | yáo dòng | yaodong (dugout used as shelter) |
| 溶洞 | róng dòng | karst cave |
| 洞穴 | dòng xué | cave; cavern |
| 山洞 | shān dòng | cavern; cave |
| 洞察 | dòng chá | to see clearly |
| 涵洞 | hán dòng | culvert; covered drain |
| 风洞 | fēng dòng | wind tunnel |
| 洞房 | dòng fáng | secret inner room; bridal room |
| 地洞 | dì dòng | a dug-out; a burrow |
| 一杆进洞 | yī gān jìn dòng | (golf) hole in one |
| 克孜尔千佛洞 | Kè zī ěr qiān fó dòng | Kezil thousand-Buddha grotto in Baicheng 拜城, Aksu 阿克苏地区, Xinjiang |
| 冰洞 | bīng dòng | hole in ice; crevasse |
| 凹洞 | āo dòng | cavity; pit |
| 别有洞天 | bié yǒu dòng tiān | place of charm and beauty; scenery of exceptional charm; completely different world |
| 千佛洞 | qiān fó dòng | thousand Buddha grotto; refers to Mogao caves 莫高窟 in Dunhuang 敦煌, Gansu |
| 坑洞 | kēng dòng | hole; pit; pothole |
| 大地洞 | dà dì dòng | cavern |
| 大浦洞 | Dà pǔ dòng | Taepodong, North Korean rocket series |
| 大浦洞二 | Dà pǔ dòng èr | Taepodong 2, North Korean rocket |
| 大浦洞二号 | Dà pǔ dòng èr hào | Taepodong 2, North Korean rocket |
| 小岩洞 | xiǎo yán dòng | grotto |
| 小洞不堵沉大船 | xiǎo dòng bù dǔ chén dà chuán | A small hole not plugged will sink a great ship. |
小洞不堵，
大洞受苦 | xiǎo dòng bù dǔ ,
dà dòng shòu kǔ | A small hole not plugged will make you suffer a big hole (idiom). A stitch in time saves nine. |
小洞不堵，
大洞吃苦 | xiǎo dòng bù dǔ ,
dà dòng chī kǔ | A small hole not plugged will make you suffer a big hole (idiom). A stitch in time saves nine. |
小洞不堵，
大洞难补 | xiǎo dòng bù dǔ ,
dà dòng nán bǔ | If you don't plug the small hole, the big hole will be hard to repair (idiom). A stitch in time saves nine. |
| 小洞不补大洞吃苦 | xiǎo dòng bù bǔ dà dòng chī kǔ | A small hole not plugged will make you suffer a big hole (common saying); a stitch in time saves nine |
| 库木吐拉千佛洞 | Kù mù tǔ lā qiān fó dòng | Kumutula thousand-Buddha grotto in Kuqa, Xinjiang |
| 引蛇出洞 | yǐn shé chū dòng | lit. to pull a snake from its hole; to expose a malefactor (idiom) |
| 挖洞 | wā dòng | to dig a hole |
| 柏克里克千佛洞 | Bó kè lǐ kè qiān fó dòng | Paziklike thousand-Buddha grotto in the Turpan basin, Xinjiang |
| 水帘洞 | Shuǐ lián Dòng | Shuilian Cave; Water Curtain Cave |
| 洞口县 | Dòng kǒu xiàn | Dongkou county in Shaoyang 邵阳, Hunan |
| 洞天 | dòng tiān | paradise; heavenly or beautiful place; fairyland |
| 洞孔 | dòng kǒng | hole |
| 洞察一切 | dòng chá yī qiè | to see everything clearly |
| 洞察力 | dòng chá lì | insight |
| 洞庭湖 | Dòng tíng hú | Dongting Lake in northeast Hunan province |
| 洞悉 | dòng xī | to clearly understand |
| 洞房花烛 | dòng fáng huā zhú | bridal room and ornamented candles; wedding festivities (idiom) |
| 洞房花烛夜 | dòng fáng huā zhú yè | wedding night |
| 洞穿 | dòng chuān | to penetrate; to pierce; to see clearly; to have an insight into |
| 洞窟 | dòng kū | a cave |
| 洞若观火 | dòng ruò guān huǒ | clear as a flame (idiom); to see things absolutely clearly |
| 洞见 | dòng jiàn | insight; to see clearly |
| 洞鉴 | dòng jiàn | to examine deeply; to inspect closely |
