Your aunt's daughter is your first cousin, and her son is your first cousin, once removed.
First cousins, twice removed. Aunts daughter is your cousin. Aunts daughters daughter is cousin once removed Aunts daughters daughters daughter is cousin twice removed.
2nd Cousin
Your mother's aunt's son is her first cousin and your first cousin, once removed.
She is your third cousin.
The father's son is the uncle of the son of the father's daughter.
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.
Your grandson is the great-nephew of your brother.
They'd be your cousin.
Your aunt's daughter is your first cousin.
They are your second cousin.
the daughter's cousin
aunts, cousins, daughters, sons, and friend.