Cognomen ريكس (Rex 
, Rix 
, ريكس 
) , in all the world, is a common last name. The family name ريكس is habitual in Greenland, where it is quite a common surname, Guernsey, and Denmark (explore the name in all countries). Not in comparison with a country's population, it is the most numerous in the United States, Sudan, and Germany. More prevalently, ريكس is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Rex | Germany, Philippines, Papua New Guinea, United States, United Kingdom |
| Rix | Germany, Philippines, Democratic Republic of the Congo, United States, United Kingdom |
| ريكس | Sudan, Saudi Arabia |
| Reks | Germany, Nigeria, Philippines, United States, United Kingdom |