noun, feminine

arrière-grand-tante

/a.ʁjɛʁ.ɡʁɑ̃.tɑ̃t/

noun, feminine/a.ʁjɛʁ.ɡʁɑ̃.tɑ̃t/plural: arrière-grandes-tantes

arrière-grand-tante is feminine in French.

great-grandaunt

From arrière- + grand-tante.