If your father's third cousin is an uncle because his brother or sister has a child, then that child and you are fourth cousins.If your father's third cousin is an uncle because his wife has a brother or sister who has a child, then that child and you are not related to each other.
Your great great uncle's great great grandson is your third cousin once removed.
Season 3
Your great-great-great uncle's great-great grandchild is your third cousin, once removed.
Your uncle's nephew could be:you, if you are a boyone of your brothers, if you have anyyour first cousin, if your parent and your uncle have a third sibling who has a child who is a boy
The brother of your great grandfather is your great great uncle. Your great great uncle's great grandchildren are your third cousins.
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.
If your great great uncle (the brother of your great grandparent) had a great great granddaughter, you would be third cousins, once removed.
That person would be either me or my sister...if the cousin of me great uncle was my great grandfather. If the cousin was another of my great uncles, then the person would be my cousin. Example 1: My dad has a brother who is my uncle. That uncle has a father who is my great uncle. If his father or mother had sisters or brothers who had kids, these kids would be cousins to this great uncle. one of them could be my grandfather. so my grandfather's granddaughter would be me if I am a girl or my sister if I am a boy. Example 2: In any level of the family tree there can be cousins...children of my uncle or aunt. when they have kids they are second cousins...children of first cousins. If these second cousins have kids, they all are third cousins. So since my great uncle had a cousin which was 2 generations above me...the next generation would be second cousins and the third generation would be third cousins. If my grandfather was not the cousin in question, then the cousin would be someone else on the same generation level, 2 levels above me and the granddaughter would be on my level and therefore my third cousin.
Your grandfather's 3rd great grand uncle (or great-great-great-great uncle) is the brother of your 5th great-grandparent (or great-great-great-great-great grandparent). He is therefore your 6th great grand uncle (or great-great-great-great-great-great-great uncle)
A third cousin is just that, a third cousin, there is no other name for the relationship.
If your great grandmother's husband is your great grand father, as is usually the case, then his great great nephew is your third cousin, and his great great great great great nephew is your third cousins, thrice (3 times) removed. If your great grandmother's husband is not your great grandfather, then you are not related to any of his nephews.