Can anyone explain why we say Great-aunt/uncle but grand niece/nephew?

I have never heard anyone say grand niece

Most people will just say niece but if they want to cut it short, they will use grand neice, rather than say daughter of my neice.

I’ve personally never been called Grand Nephew but I lived with my Great Aunt in high school. I think the term “Grand” is in proper relation to kids. You are a Grand to your “Grand” parents, through relation of your parents. Your are also a Grand to your “Great” aunt/uncle through your parents also. Also, your Grand-parents are Grand, so your aunt/uncle can’t be Grand because they aren’t a straight relation, but they are Great because they ARE related to you.

I am a Great Aunt, but I won’t be a Grand Aunt until my Niece’s daughter has a baby. Isn’t that how it goes? So, she’s my Great Niece, but when she has a baby,(which will be this Spring!) that baby will be my Grand something? I am not sure, but there are so many of us, we need some way of labeling the generations. Gah! Too many of us! Too many Great Great Greats…. or should we just say 3G?

Side note: In Norwegian there are separate words for cousin, to show whether it is a male or female cousin. That seems logical.

I’ve never heard anyone use ‘grand niece’ or ‘grand nephew’. We’ve always used ‘great niece’ and ‘great nephew’.

Either way it makes very little sense.
Parents is 1st
Grand parents is 2nd generation removed
Great grand parents are 3rd generations removed
So it should follow that it be
niece 1 generation removed
grand niece 2nd generation removed
great niece 3 generation removed (of course no one really bothers but it should be grand niece, not great) Same as it would make sense for the aunt to be a grand aunt not a great aunt