Cognomen ไสน (Sain 
, ไสน 
) , in all the world, is a widespread last name. The surname ไสน is characteristic of Bosnia and Herzegovina, where it is quite a common surname, Bahrain, where it is quite a rare surname, and Oman. In absolute terms, it is commonest in India, Indonesia, and the United States. Much less frequently, ไสน is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sain | Indonesia, India, Pakistan, United States, Myanmar |
| ไสน | Thailand |