The grandson of your first cousin is your first cousin, twice removed.
The grandson of your second cousin is your second cousin, twice removed.
If you are talking about the grandson of a cousin who is once, twice, or more times removed, the possible relationships become more complicated to describe.
Your uncle's sons and daughters are your first cousins.
You do you call your sons's son your "grandson" !
Cousine
The sons of your father's sister are your first cousins.
Your mom and her uncle's son are cousins, of the same generation, first cousins. Your mom's uncle's son is your first cousin, once removed (by one generation). If he has children, they will be your second cousins. (Children of first cousins are second cousins to each other.)
third cousin once removed
Our cousins are our mothers sisters son :)
They share a common Grandparent. That makes them first cousins.
Your granddaughter and your sister's grandson are second cousins.
Your first cousin is your son's first cousin once removed.
basiclly there called brothers .-.-.-.-.-.-. basically* for one... and two no, they wouldn't be called brothers. If it was their parents sons then yeah, but if it's the sons of brothers then they'd be cousins. That's practically like saying one brother got married and had a son, then the other did too and had a son as well. The relation of the sons would be cousins.
Your cousin's son is your cousin, once removed, but it is probably best to call him or her by their first name.