Surname Tercius (Tercius 
) , worldwide, is a very rare last name. The cognomen Tercius is habitual in Honduras, where it is a very rare surname, Brazil, where it is an extremely rare surname, and the United States. More prevalently, Tercius is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Tercius | Brazil, Philippines, India, South Africa, United States |