nephew; niece
He's my nephew, because his father is my eldest brother
grandchild; grandson; granddaughter
My grandparents have 40 grandchildren in all
grandnephew; grandniece
child
How many children have you got?
What amusements do you have for your children?
I (used for addressing one's uncle/aunt/grandfather/grandmother)
you (used for addressing one's nephew/niece/grandchild)
Did you enjoy yourself last night ?