Cognomen Thomasia (Thomasia 
) , across the world, is a rare surname. The surname Thomasia is habitual in Ethiopia, where it is a very rare surname, Netherlands, and Brazil, where it is an extremely rare surname. Also, Thomasia is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Thomasia | Ethiopia, South Africa, Ghana, United States, Brazil |