| 漏洞HSK 5 | lòu dòng | leak; hole; gap; loophole | |
| 窑洞 | yáo dòng | yaodong (a kind of cave dwelling in the Loess Plateau in northwest China); Classifiers: 孔 | |
| 空洞HSK 6 | kōng dòng | cavity; empty; vacuous | |
| 黑洞HSK 5 | hēi dòng | (astronomy) black hole | |
| 洞口HSK 5 | dòng kǒu | Dongkou county in Shaoyang 邵阳 , Hunan |
| 1 | This hole looks very deep. | |
| 2 | This software has security vulnerabilities. | |
| 3 | There are many caves in the deep forests. | |
| 4 | It takes some slow crawling to get through this hole. | |
| 5 | Hackers infiltrated the database through the vulnerability. |