The masculine noun 'strănepot' and the feminine noun 'strănepoată' are the Romanian equivalents of 'Great Grandchild' in their respective meanings as 'Great Grandson' and 'Great Granddaughter'.
Nepot is a Romanian equivalent of 'Grandchild' in the sense of 'Grandson', and Nepoată in the sense of 'Granddaughter'.
Your sister's great grandchild is your great great niece or great great nephew.
Grandchild
Your great uncle's grandchild is your second cousin.
Your great-great-great uncle's great-great grandchild is your third cousin, once removed.
Your great grandmother's sister is your great great aunt. Her great grandchild is your third cousin.
Your child and your nephew are first cousins, so your grandchild and your nephew are first cousins once removed.
NO Nadia Comanici is Romanian and Boyanka Angelova is Bulgarian.
You and your uncle's great grandchild are first cousin, twice removed.
Her first great grandchild will be born next December.
Your brother's great grandchild is your great great nephew (if a boy) or great great niece (if a girl). You are their great great aunt.
The grandchild of your great grandmother's sister is your second cousin, once removed.