grandniece
noun
- sibling's granddaughter
Wiktionary
noun
Etymology: Etymology tree English grand- English niece English grandniece From grand- + niece.
- A granddaughter of one's sibling; a daughter of one's nephew or niece. (Brother's granddaughter: fraternal grandniece. Sister's granddaughter: sororal grandniece.)
“Then come […] the Duchess’s grandnieces Zwile and her little sister Gloria.”