| 三硝基甲苯 | sān xiāo jī jiǎ běn | trinitrotoluene (TNT) |
| 三碳糖 | sān tàn táng | triose (CH20)3, monosaccharide with three carbon atoms, such as glyceraldehyde 甘油醛 |
| 三磷酸腺苷 | sān lín suān xiàn gān | adenosine triphosphate (ATP) |
| 三棱草 | sān léng cǎo | sedge herb (Cyperus rotundus) |
| 三穗 | Sān suì | Sansui county in Qiandongnan Miao and Dong autonomous prefecture 黔东南州, Guizhou |
| 三穗县 | Sān suì xiàn | Sansui county in Qiandongnan Miao and Dong autonomous prefecture 黔东南州, Guizhou |
| 三等分 | sān děng fēn | trisection (math.); trisecting an angle |
| 三等分角 | sān děng fēn jiǎo | trisection (math.); trisecting an angle |
| 三级 | sān jí | grade 3; third class; category C |
| 三级士官 | sān jí shì guān | staff sergeant |
| 三级片 | sān jí piàn | third category movie (containing sexual or violent content) |
| 三级跳 | sān jí tiào | triple jump (athletics); hop, skip and jump |
| 三级跳远 | sān jí tiào yuǎn | triple jump (athletics); hop, skip and jump |
| 三索锦蛇 | sān suǒ jǐn shé | copperhead race (Elaphe radiata), kind of snake |
| 三维 | sān wéi | three dimensional; 3D |
| 三维空间 | sān wéi kōng jiān | three-dimensional space; 3D |
| 三义 | Sān yì | Sanyi township in Miaoli county 苗栗县, northwest Taiwan |
| 三义乡 | Sān yì xiāng | Sanyi township in Miaoli county 苗栗县, northwest Taiwan |
| 三聚氰胺 | sān jù qíng àn | melamine C3H6N6 |
| 三联书店 | sān lián shū diàn | Joint Publishing Co.,, Hong Kong |
| 三联管 | sān lián guǎn | triplet |
| 三胚层动物 | sān pēi céng dòng wù | triploblastic animals (having three germ layers) |
| 三脚两步 | sān jiǎo liǎng bù | hurriedly; just a few steps away |
| 三膲 | sān jiāo | variant of 三焦, triple foci, the three visceral cavities of traditional Chinese medicine |
| 三自 | sān zì | abbr. for 三自爱国教会, Three-Self Patriotic Movement |
| 三自爱国教会 | sān zì ài guó jiào huì | Three-Self Patriotic Movement, PRC government-sanctioned Protestant church from 1949 |
| 三自教会 | sān zì jiào huì | Three-Self Patriotic Movement, PRC government-sanctioned Protestant church from 1949 |
| 三色 | sān sè | three colors |
| 三色堇 | sān sè jǐn | pansy |
| 三色紫罗兰 | sān sè zǐ luó lán | pansy |
| 三色猫 | sān sè māo | calico cat |
| 三芝 | Sān zhī | Sanchih township in Taipei county 台北县, Taiwan |
| 三芝乡 | Sān zhī xiāng | Sanchih township in Taipei county 台北县, Taiwan |
| 三茶六饭 | sān chá liù fàn | lit. to offer three kinds of tea and six different dishes; to be extremely considerate towards guests (idiom) |
| 三菱 | Sān líng | Mitsubishi |
| 三叶星云 | Sān yè xīng yún | Trifid Nebula M20 |
| 三叶草 | sān yè cǎo | clover; trefoil |
| 三叶虫 | sān yè chóng | trilobite |
| 三藏 | Sān zàng | Tripitaka (602-664) Tang dynasty Buddhist monk and translator, who traveled to India 629-645; same as 玄奘 |
| 三藏法师 | Sān zàng fǎ shī | Tripitaka (602-664) Tang dynasty Buddhist monk and translator, who traveled to India 629-645; same as 玄奘 |
| 三藩之乱 | sān fān zhī luàn | Three feudatories rebellion against Qing 1673-1681 during the reign of Kangxi |
| 三藩叛乱 | Sān fān pàn luàn | rebellion against the Qing of 1670s, pacified by Kangxi |
| 三藩市 | Sān fān shì | San Francisco (California) |
| 三苏 | Sān Sū | the Three Su father and sons; refers to northern Song literati Su Xun 苏洵, Su Shi 苏轼 and Su Zhe 苏辙 |
| 三号木杆 | sān hào mù gān | spoon (golf) |
| 三号电池 | sān hào diàn chí | C size battery (PRC); AA battery (Taiwan); see 二号电池 (C battery in Taiwan) and 五号电池 (AA battery in PRC) |
| 三亲六故 | sān qīn liù gù | old friends and relatives |
| 三角债 | sān jiǎo zhài | chain of debt |
| 三角凳 | sān jiǎo dèng | trestle stool; folding chair |
| 三角座 | sān jiǎo zuò | Triangulum (constellation) |
