Formal:
* Baba agba (literally "old father") - This is the most common and formal way to address a grandfather.
Informal:
* Baba (literally "father") - This is a more informal way to address a grandfather, often used by younger generations.
* Baba nla (literally "big father") - This is another informal way to address a grandfather, usually used by grandchildren.
Specific terms:
* Baba nla (literally "big father") - This term is often used to specifically refer to a paternal grandfather.
* Baba iya (literally "mother's father") - This term is used to refer to a maternal grandfather.
The best way to address a grandfather in Yoruba will depend on the context and your relationship with him.