Your cousin's husband is called brother-in-law, haha,just like call you sister's husband...
Nieces.
aunts, cousins, daughters, sons, and friend.
Your daughters husband is you son-in-law.
Your grand daughter's husband is your grandson-in-law.
Uncle
Your aunts and uncles are the sisters and brothers of your parents. So they are "blood related." But you also call the husband of your mother's sister your uncle, and he is not "blood related." So aunts and uncles are not always really related to you.
Mary Lee Cantwell's husband was literary agent Robert Lescher. They had two daughters - Katherine and Margaret.
Son-in-law.
the daughter's cousin
London with her husband and twin daughters.
She had her husband, Kind Prasutagus, and two daughters.
He is your grandson by marriage or grandson in-law.