What does 이모 (imo) mean in Korean?

이모        아줌마

  [i-mo]     [a-jum-ma]

이모 literally means “aunt from your mother's side.” While 아줌마 means middle aged lady / madam.” but 이모 is used in Korean culture to call friendliness even if they are not related. 이모 is used more than 아줌마 to call middle aged lady employees in restaurants and shops.