What is the child of my cousin to me?
Consequently, what are cousins children to each other?
Children of your cousin are actually called your “first cousins once removed.” So if you're wondering what relationship your cousin's child is to you, that's it — your first cousin once-removed! Your cousin's child is NOT your second cousin as is commonly believed.
Keeping this in view, who is my 2nd cousin?
Second Cousins. You and the child of your parent's cousin are second cousins. The two of you share at least one set of great-grandparents in common. Think of them as first cousins, since they are in the same generation as you, but with an added generation between yourselves and your linking ancestor.
While from a genealogy standpoint, your cousin's child is your first cousin once removed, but the common name to call them is niece or nephew. They would call you aunt or uncle, and your children would simply call them cousins… although of course, they are really second cousins.