Your father and your aunt are siblings (brother and sister)
The grandchildren of siblings are second cousins to each other.
Your aunt's grandson is the son of your First Cousin and is therefore your First Cousin once removed Ref: http://freepages.genealogy.rootsweb.ancestry.com/~gentutor/chart.html
ya mum!
Your son and your aunt's child are first cousins, so your son and your aunts grandson (the son of your aunt's child) are first cousins, once removed.
it's like your 3rd cousin
Your grandfather's brother's grandson is your great uncle's grandson. The grandchildren of great aunts and great uncles are your second cousins.
They are your Uncles and or Aunts.
First cousins, twice removed. Aunts daughter is your cousin. Aunts daughters daughter is cousin once removed Aunts daughters daughters daughter is cousin twice removed.
Your aunt's daughter is your first cousin.
Your aunt's baby would be your cousin
Your aunts' mother-in-law.
No relationship at all, you don't share a common ancestor.
2nd Cousin