Senses
婶婶/ 嬸嬸 aunt
wife of one's father's younger brother
婶婶/ 嬸嬸 sister-in-law
one's younger brother's wife (used by the wife of the elder brother)
婶婶/ 嬸嬸 auntie
respectful form of address for a married woman of one's parents' generation who is younger than them