'Niece' is what a little girl is to her uncle. 'Nephew' is what a little boy is to his uncle. The children also are the niece and the nephew of their aunt.
niece
Lindsey
niece
Uncle Albert/Admiral Halsey Go Away Little Girl
This will depend upon how many girls have the same uncle. If you are referring to one girl, the apostrophe would be between the l and the s: the girl's uncle. If you are referring to more than one girl, the apostrophe would be after the s: the girls' uncle. Both versions indicate possession - the uncle of the girl or the uncle of the girls.
Nephew (boy) or niece (girl)
Your uncle is your child's great uncle. Your child is his great niece (if a girl) or great nephew (if a boy).
Your great uncle is the brother of one of your grandparents. If you are a boy, you are your great uncle's great nephew. If you are a girl, you are your great uncle's great niece.
She is a niece.
Eva
Eva
An aunt if its a girl. An uncle if its a boy.