cousins.
Your nephew's son is your great nephew.
A nephew is a cousin to his aunt's son.
Your nephew's daughter's son is your great-great nephew. Your nephew's daughter is your great niece.
Your nephew.
Your husband's sister's son is your nephew, just as your sister's son is your nephew.
great nephew
Cousin brother
Your son and your nephew are First Cousins. The children of your nephew and the children of your son are Second Cousins to each other.
The child of your nephew is your great nephew (if a son) or your great niece (if a daughter).
Your sister-in-law's son is your nephew.
Your brother-in-law's son is your nephew
Your sister's son is her grandson and your great nephew. Some use the term "grand nephew."