Your nephew is your daughter's first cousin. So your daughter's daughter (your granddaughter and your nephew are first cousins, once removed.
Your wife's nephew is also your nephew. His daughter is your (and your wife's) great niece.
The correct term would be "daughter's" if you are referring to something that belongs to one daughter. For example, "My daughter's book." On the other hand, if you are referring to something that belongs to multiple daughters, you would use "daughters." For example, "My daughters' toys." The use of the apostrophe indicates possession or ownership.
Nephew
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 daughters have short term memories.
The female equivalent of "nephew" is "niece." A niece is the daughter of a person's sibling or sibling-in-law. This term is commonly used to describe the familial relationship between an aunt or uncle and their sibling's daughter.
He would be your grand nephew; you would be his great-aunt.
Generally, they would be referred to as "in-laws" as a generic term. Or, alternately, as "our daughter's in-laws". In person, you would introduce them as "our son-in-law's parents".
Your sister's son is your nephew and you are their aunt or uncle. Their baby would be your great nephew. Some use the term grandnephew, but great is more accurate.
Oh, what a lovely question! You can call your nephew's daughter your great-niece. It's a beautiful title that reflects the special bond you share with her. Just like a happy little tree in a painting, your relationship will continue to grow and flourish with each passing day.
Your wife's nephew is your nephew, but the English language has no relationship term for your nephew's wife. Just call her "my nephew's wife."
an adolescent, teenager, son, daughter, niece, nephew, cousin