If your father and someone else's father are first cousins, then you and that someone else are second cousins.
Your mother's sister's children are your 1st cousins.
You and the son of your uncle are first cousins to each other.
Your father's first cousins are your first cousins, once removed.
They are cousins.
Your father has a cousin so they are first cousins, meaning that your grandpa, and the other guy's grandpa were real brothers. Therefore, you and that other guy's kids are second cousins.
You're using a couple of vague terms there. They're probably your "cousins" also, but it's possible they're "no particular relation".I'm going to use the male terms throughout just to save typing. Take it as a given that when I say uncle, I really mean "uncle or aunt", when I say father, I really mean "father or mother."It's kind of weird to ask about your uncle's cousins, because if they're your uncle's cousins, they ought to be your father's cousins too. Unless you mean "uncle" as in "your father's brother's husband" (hey, I did say male terms throughout), in which case his cousins are basically "no relation" to you.However, your father's cousins are your cousins also, except "once more removed" from whatever they were to your father.If they were his first cousins, they're your first cousins once removed. And so on. It does get a little tricky, because your father's first cousins once removed could either be your first cousins twice removed, or your second cousins, but "how do you determine exactly what kind of cousins two people are" really deserves its own separate question.
Your daughter and your first cousin are first cousins, once removed.
They are first cousins.
The son of your dad's first cousin is your second cousin. 1. First cousins share two of the same grandparents. 2. Second cousins share the same great-grandparents but not the same grandparents.
Your Father's first cousins are also your first cousins, once removed.
The children of your mother's first cousins are your second cousins. The children of your mother's second cousins are your third cousins. And so forth.
If B is a first cousin to your father, they have the same grandparents. Their children will share a pair of great grandparents and will be second cousins to each other.