What is Lineage Relation between These Two Son's?

Question:

What is Lineage Relation between These Two Son's?

Brother and Sister by Blood.
Brother has daughter. Sister has son(2nd. gen.)
Brother's daughter has son.(3rd gen)
What is relation between 2nd. gen.(Sister's) son and 3rd. gen(B. daughter's) son?
I say second uncle, cousin(Uncle's daughter) says "cousin"; who is right?

Best Answer - Chosen by Asker: First Cousin once removed is correct. If two people share the same grandparent they are first cousins. If one of those cousins has a child then that child would be one generation removed from the first cousin making them first cousins once removed.