* Ewythr: This is the most common and general term for uncle.
* Tad-cu: This literally means "father-grandfather," and is used for a father's brother.
* Mam-gu: This literally means "mother-grandfather," and is used for a mother's brother.
It's worth noting that the term "Ewythr" can also be used for a mother's brother, but "Tad-cu" and "Mam-gu" are more specific and commonly used for that relationship.