Technically, the sister and brother of one of your grandparents are your grand-aunt and grand-uncle. "Grand" shows that it is one generation away- the generation of your grandparents. "Great" is properly added to those generations beyond "grand." However, in common usage people generally refer to the siblings of grand parents as great-aunt and great-uncle.
You would call people cousins who are descended from the siblings of your parents, grand parent, great grandparents, etc.
Grand Parents siblings.
Offspring who have the same parents are called siblings.
The parents of a nephew are your siblings (a brother or a sister).
brother or sister
Any children of your parents' siblings are your cousins.
your mothers mother is called your grandmother. and your mothers father is called your grandfather.
The daughter of your brother or sister is your niece.
no siblings are not also parents. siblings is a word for brothers and sisters so you do not have to say my brothers and sisters all the time.
no siblings are not also parents. siblings is a word for brothers and sisters so you do not have to say my brothers and sisters all the time.
You could call them and tell them that you care about them , or if you live nearby, go and visit them.
Your dad's mum and dad are your paternal grand parents, they are your granddad and your grandma.