Last name Cayus (Cayus 
) , in the entire world, is a very rare cognomen. The surname Cayus is characteristic of Tanzania, where it is a very rare surname, Malaysia, and Argentina, where it is an extremely rare surname. Much less frequently, Cayus is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Cayus | Argentina, Tanzania, United States, Malaysia, Brazil |