Cognomen นิจน์ (Ni 
, Knijn 
, นิจน์ 
) , in the entire world, is a widespread family name. The last name นิจน์ is habitual in Mongolia, where it is a widespread surname, Myanmar, where it is a common surname, and Malaysia, where it is quite a common surname (explore the name in all countries). Not in comparison with a country's population, it is commonest in China, Myanmar, and India. Likewise, นิจน์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ni | China, Indonesia, India, Mongolia, Myanmar |
| Knijn | China, Netherlands, Spain, United States, United Kingdom |
| นิจน์ | Thailand |