Whether on the mother's (maternal) or father's (paternal) side, the parents' parents are called grandparents. A son of a child is a grandson. The grandson's son is a great-grandson. It is also possible to have, now, a step-grandparent and step-grandson/great-grandson. In the past (through mid to late 1900s), when there were more than 2 sets of grandparents, they were all considered as equals (no "step" added).
a great grandson.
great-grandson
The son of a great grandson is a great greatgrandson.
GSon for Grand Son GDau for Grand Daughter
Your husband's sister is your sister-in-law. Her son is your husband's nephew, and therefore your nephew. The son's daughter is your husband's great nephew (or grand nephew) and therefore your great nephew (or grand nephew).
If they are not your daughter's children, then they are all step children. They will be called step-grand children. If they have children, those are step-great grand children. If they are your daughter's children, you must know that they are your grand children as they are directly related to you.
Your niece's son is your grand-nephew. You are the child's grand aunt, or grand uncle (whichever applies).
Your nephew's son is your grand nephew or great nephew. Some people say one, some say the other.
My son and grand-son.
your son will be grandfather of your great grand son. :)
Your niece's son's daughter is your great grand niece. Your niece's son is your grand nephew or your great nephew, whichever term you prefer.
Your great aunt's son is your parent's first cousin and your first cousin, once removed.
no
Yes Emeka Jaja Wachuku is Jaja Wachuku's Grand son. Emeka is the first son of Jaja Wachuku's second son, Emenuwa.