auntie (n.) Look up auntie at Dictionary.com
1787, also aunty, familiar diminutive form of aunt. It also was a form of kindly address to an older woman to whom one is not related, originally in southern U.S., of elderly slave women.
The negro no longer submits with grace to be called "uncle" or "auntie" as of yore. ["Harper's Magazine," October 1883]