Two people whose great grandparents were siblings are third cousins to each other.
The children of siblings are first cousins.
The grandchildren of siblings are second cousins to each other.
The great grand children of siblings are third cousins to each other.
If you and someone else have grandparents who were second cousins, you are related as fourth cousins.
If your grandparents were first cousins, then your are third cousins.
The two share a common ancestor. There is a difference of one generation. They would be first cousins once removed.
If two people have grandparents who are second cousins, it means that their great-grandparents are siblings or cousins. Therefore, the two people are third cousins to each other.
Two people who have the same great grandparents but have no closer relationship are second cousins. Their parents are first cousins and their grandparents are siblings.
You and your 4th cousin's have the same great great great grandparents. Perhaps a more precise way to describe your connection to your fourth cousin is that you have great great grandparents who were siblings
great great (etc.) grandparents great grandparents grandparents + great uncles and great aunts parents + uncles and aunts [=parents' siblings] siblings + cousins [=uncles' and aunts' children] children + nephews and nieces [=siblings' children] grandchildren great gandchildren great great (etc.) grandhildren also cousins and second cousins [=(great-)grandparents' descendants]
great great (etc.) grandparents great grandparents grandparents + great uncles and great aunts parents + uncles and aunts [=parents' siblings] siblings + cousins [=uncles' and aunts' children] children + nephews and nieces [=siblings' children] grandchildren great gandchildren great great (etc.) grandhildren also cousins and second cousins [=(great-)grandparents' descendants]
Two people who share the same great great grandparents are third cousins. To find a cousin relationship, find the common ancestor. If common ancestor is grandparents, they are 1st cousins. If common ancestor is great-grandparents, they are 2nd cousins. If common ancestor is great-great-grandparents, they are 3rd cousins.
You, your mom, your dad, your siblings, your grandparents, your great grandparents, all people associated with you, and last but not least your dog
If you have the same great great grandparents as someone else, and have no closer common ancestors, then your great grandparents were siblings and you are third cousins to each other.
First cousins are the grandchildren of siblings. Sixth cousins are the great great great great great grandchildren of siblings. Therefore, first cousins are much more closely related than sixth cousins.
Grandparents are not "removed". Grandparents are in your direct line and with each generation going back you add a "great". See related link.Grandparents are not "removed". Grandparents are in your direct line and with each generation going back you add a "great". See related link.Grandparents are not "removed". Grandparents are in your direct line and with each generation going back you add a "great". See related link.Grandparents are not "removed". Grandparents are in your direct line and with each generation going back you add a "great". See related link.
You would call people cousins who are descended from the siblings of your parents, grand parent, great grandparents, etc.
ALL cousins are related "by blood" because the cousin relationship depends on descent from a common ancestor. No one can become a cousin by "marrying in." Some people feel a need for a term to describe the spouse of a cousin, and they sometimes use the term "cousin-in-law", but just as your "brother-in-law" is not your brother, your "cousin-in-law" is not your cousin. Third Cousins are descended from a common great great grandparent.