also: ひいばば · ひばば · ひおおば
noun
great-grandmother
Refers to the mother of one's grandparent. The reading そうそぼ is formal, while ひいばば is colloquial and often used by children.
曾祖母は今年で95歳になります。
My great-grandmother will be 95 this year.
ひいばばの家に行くのが楽しみだ。
I look forward to visiting my great-grandma's house.