My nephew has a daughter. What am I?

A cousin

Are you sure? This is my brother's son who has a daughter. I would be a cousin?

Try uncle then. I wasn't quite sure what your question pertained to. It sometimes helps to have more background in a question. It is very difficult sometimes trying to be a mind reader.

I am not an expert in genealogy. In fact I don't think we have any experts here in that field, but I am pretty sure you would be an uncle.

Tick

She is your great-niece, so you are her great-uncle.