In all the world, 洪洙 (洪洙 
) is a very rare boy's given name. The first name 洪洙 is habitual in Eastern Asia, particularly China, where it is an extremely rare male name. Very seldom, 洪洙 is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| 洪洙 | China |