Grandma, Old Lady, Old Woman
Noun
おばあちゃん
お婆ちゃんに、嘘をついたことで責められた。
My grandma accused me of telling lies.
An old woman is who this is. Then, you add ちゃん for the name ender. You add お to be nicer. This person is a granny or grandma or old lady or old woman.
The reading isn't the ば you learned with the kanji. It's a slightly longer ばあ, because you gotta be nice, you know? Also, the person you thought was a granny is actually a sheep. Baaaa! (ばあ).