Surname ซ้อ (So 
, 嫂 , Drill 
) , worldwide, is a widespread cognomen. The cognomen ซ้อ is characteristic of Hong Kong, where it is a widespread surname, British Virgin Islands, where it is a common surname, and Cayman Islands (explore the name in all countries). In absolute terms, it is commonest in Hong Kong, Egypt, and China. Likewise, ซ้อ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| So | Taiwan, Hong Kong, China, Egypt, Myanmar |
| 嫂 | China |
| Drill | China, Indonesia, United States, Malaysia, India |