Second cousins are people who share the same great-grandparents, but not the same grandparents or parents. For example, using yourself as the reference point, your aunt's child is your first cousin and your great aunt's grandchild is your second cousin.
Second cousins are the grandchildren of siblings.
The degree (first, second, third cousin, etc.) indicates one less than the minimum number of generations between either cousin and the nearest common ancestor; the remove (once removed, twice removed,etc.) indicates the number of generations, if any, separating the two cousins from each other (Wikipedia).
A second cousin are the children of two first cousins. They are usually first cousins that share great grandparents.
If you are his second cousin, he is your second cousin
Asking about your second cousin's cousin's cousin is asking about a complex but poorly defined relationship. Are the cousins of the second cousin his first cousin, second cousin, fifth cousin twice removed, or something else. It is likely that a cousin's cousin's cousin is not related to you at all. It is also possible that your second cousin's first cousin's first cousin is also your second cousin.
Your second cousin's niece is the daughter of your second cousin's brother or sister. Your second cousin's brother or sister is also your second cousin, so this question is the same as "How are you related to the daughter of your second cousin."The daughter of your second cousin is your second cousin, once removed.
Your first cousin's second cousin may be your second cousin as well, or may not be related to you at all.
Your child is your cousin's second cousin. (And he/she is your child's second cousin)
Your second cousin is your parent's cousin's child. You and your second cousin share a great-grandparent (not a grandparent).
No, your father's first cousin is the parent of your second cousin. Your second cousin is your father's first cousin, once removed.
He is your second cousin also
Your second cousin's daughter is your second cousin, once removed.
Your second cousin's child is your second cousin, once removed.
The child of your second cousin is your second cousin, once removed.
Your mother's second cousin is your second cousin, once removed.