You and your first cousin's daughter are first cousin, once removed, to each other.
Your child and your first cousin's child are second cousins to each other.
The grandchild of one of two First Cousins is the First Cousin, twice removed, of the other First Cousin.
Your daughter and your first cousin are first cousins, once removed, to each other.
That would make them your 2nd cousin.
second cousin
She's your second cousin.
Second cousins
Your daughter and your first cousin's son are second cousins to each other.
Your son and your niece are first cousins. Her daughter and your son are first cousins, once removed.
Your daughter and your nephew are first cousins to each other. Your daughter and your nephew's son are first cousins, once removed, to each other.
Your daughter and your niece are first cousins. Your daughter than your niece's son are first cousin's once removed. Your daughter's child and your niece's child are second cousins to each other.
Your son and your niece are first cousins to each other. Your son and your niece's son are first cousins, once removed.
Your sister's daughter and your son are first cousins to each other. Your sister's daughter and your son's daughter are first cousins, once removed to each other. Your son's daughter and your sister's granddaughter are second cousins to each other.
Your son and your nephew are first cousins to each other. Your son's daughter and your nephew are first cousins once removed.
Your nephew and your daughter are first cousins to each other. Your nephew's son and your daughter are first cousins, once removed. Your nephew's son and your daughter's child would be second cousins to each other.
Your daughter's son's son is your great grandson. Your daughter and your sister's son are first cousins. Your great grandson and your sister's son are first cousins, twice removed. Your great grandson and your sister's great grandchild are third cousins.
If by cousin you mean first cousin, your daughter and your (first) cousin's son's are second cousins to each other.
Your daughter and your sister's son are first cousins to each other. Your sister's son's daughter (her granddaughter) and your daughter are first cousins, once removed.
Your nephew and your daughter are first cousins to each other.Your nephew's son and your daughter are first cousins, once removed, to each other.