Formal:
* Periya Paattiyar: This is the most formal and respectful way to address your great grandfather. It literally translates to "Grandfather of the Grandmother". This term is typically used when addressing him in a public or formal setting.
Informal:
* Periya Thatha: This is a more informal way to address your great grandfather. It literally translates to "Big Grandfather". This term is typically used within the family.
* Periya Paattiyar Thatha: This is another common way to address your great grandfather. It combines the formal and informal terms, making it slightly more respectful than just "Periya Thatha".
Other options:
* Aachaan: This term is used to address any elderly male relative.
* Periya Kaalai: This term literally translates to "Big Old One" and can be used to address an elderly relative, but it's less common than the other options.
The best way to address your great grandfather depends on the context and your personal relationship with him.