"Ci4" • Chinese-English Dictionary
| 方根 | fāng gēn | (math.) root (as in "fourth root (∜)", 4次方根[si4 ci4 fang1 gen1]) |   |
| 三次元 | sān cì yuán | three-dimensional / the real world (cf. 二次元[er4 ci4 yuan2]) | |
| 悬梁刺股 | xuán liáng cì gǔ | to study assiduously and tirelessly (idiom) / see also 頭懸梁，錐刺股|头悬梁，锥刺股[tou2 xuan2 liang2 , zhui1 ci4 gu3] | |
| 二简 | èr jiǎn | abbr. for 第二次漢字簡化方案|第二次汉字简化方案[Di4 er4 ci4 Han4 zi4 Jian3 hua4 Fang1 an4] | |
