Answer: mawr wyr
In Welsh, great grandson is "gwyrthiog wyrion" (paternal side) or "gwyrthiog o garws" (maternal side).
The Welsh word for grandson is "hefyd."
The Welsh term for 'great grandmother' is "nain fawr".
The term for great grandfather in Welsh is "hen daid."
The Welsh word for great grandchildren is "awyrennau mawr."
"AGE" in Welsh is "OED".
Great > [Welsh] mawr
The Welsh word for grandson is "hefyd."
'Great Aunt' in Welsh is 'Hen Fodryb'
newyddion gwych means great news in welsh
ŵyr
The Welsh term for 'great grandmother' is "nain fawr".
The term for great grandfather in Welsh is "hen daid."
Your brother is your grandson's great uncle, and your grandson is your borther's great nephew. Some people would also say grand nephew and grand uncle.
Your brother-in-law is your spouse's brother. His grandson s your spouce's great nephew. (Some people say grand nephew). That makes him your great nephew, too. Your brother-in-law could also be the husband of your sister. Then your brother-in-law's grandson is your sister's grandson and your great nephew.
Have a great day/Pob hwyl i chi.
The son of your grandson is your great grandson. You are his great grandmother or great grandfather.
Your father's great grandson could be your grandson, or your great nephew.