Onba - Onba

...In Kikaijima, Amami, they were called Okura and Mukera, and as a rule, uncles and aunts from both the paternal and maternal sides were chosen. Separately from this, in the Tohoku region and elsewhere, while male heirs were called Ani, males other than heirs were called Oji and Onji regardless of age, and unmarried girls and youngest daughters were often called Oba and Onba. Even in the Chubu region, males and females other than heirs could not become independent heads or housewives of households even when they reached adulthood, and were called Oji and Oba and remained in their natal households for the rest of their lives. ...

*Some of the terminology explanations that mention "Onba" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…奄美の喜界島ではこれをオクラー，ムケーラーとよび父方母方双方のおじ･おばが選ばれるのが原則であった。　これとは別に東北地方などで，相続人の男子がアニと呼ばれるのに対して相続人以外の男子を年齢にかかわりなく，オジ･オンジと呼び，また未婚の女子や末娘などをオバ･オンバと呼ぶ例がしばしば見られた。中部地方などでも相続人以外の男子や女子は壮年になっても独立の家の主人･主婦とはなりえず，オジ･オバと呼ばれて終生生家に残留することも見られた。…

※「オンバ」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報