If you are a woman, you are your great grandmother's great granddaughter so your son is the son of her great granddaughter. But there are other possible relationships to other of her great granddaughters.
The great granddaughter could be your sister. Then your son is her nephew and she is his aunt.
The great granddaughter could be your first cousin. Then she and your son are first cousins, once removed.
The great granddaughter could be your second cousin. Then she and your son are second cousins, once removed.
Your grandfather's son is either your father or your uncle. Your daughter's grandfather is your father. or your father-in-law.So your daughter's grandfather is your grandfather's son or a brother if there is more tha one son, or, as your father-in-law, is not related to your grandfather's son at all.
Your aunt is great great aunt to your son's daughter (your granddaughter). Your granddaughter is your aunt's great great niece.
Your son's daughter is your granddaughter. Your sister is your granddaughter's great aunt.
Your grandmother's brother is your great uncle. Your great uncle's son's great granddaughter is your great uncle's great great granddaughter. Your great uncle's great great granddaughter is your second cousin, twice removed, and is your daughter's third cousin, once removed.
Your daughter's daughter is your grand daughter. Your sister's son's daughter's son is your sister's great grandson and your great great nephew. Your granddaughter and your great great nephew are second cousins, once removed ,to each other.
you will be his great great grand son/daughter..:)
Your wife's brother is your brother-in-law. His son's daughter is his granddaughter and your child's first cousin, once removed, but is not related to you. You can refer to her as "my brother-in-law's granddaughter."
. Your uncle is one of your parents brother. His son or daughter is your cousin. The granddaughter is a second cousin.
Your granddaughter could be your son's daughter, or your son's niece.
Your great grandmother's brother is your great great uncle. Your parent and the grandson of your great great uncle are Second Cousins. Therefore you and the grandson of your great great uncle are Second Cousins, once removed.
Your sister's son is your nephew. Your sister's granddaughter is your great niece.
Your sister's son is her grandson and your great nephew. Some use the term "grand nephew."