Family name 第 (ទី 
, 第 
, Dì 
) , in the world, is a common cognomen. The last name 第 is characteristic of Cambodia, where it is a common surname, South Korea, where it is quite a rare surname, and China. Very seldom, 第 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| ទី | Cambodia |
| 第 | China |
| Dì | Vietnam, China, Algeria, Tunisia, Morocco |
| 제 | South Korea |