also: おばちゃま
noun
Affectionate, honorific term for one's own grandmother or an elderly woman, used mainly by children or in familiar contexts. The contracted form おばちゃま is also common.
おばあちゃま、今日は何を作ってくれるの？
Grandma, what are you making for us today?
おばちゃま、一緒に遊ぼう！
Granny, let's play together!
Derived from おばあさん (grandmother) with the honorific suffix ちゃま, a blend of ちゃん and さま, used in child-directed or affectionate speech.