all women that are younger than your mum.

house helper / babysitter / female relative 阿姨 = ā-yí

阿姨：you can call all of the women whose age are close to your mother's but who has NO blood relationship with your family.

ayi 阿姨 ? aiyi 爱意?

Are you sure it is aiyi instead of another word “ayi”? I do not know aiyi, either, but there is another word called "阿姨". This might helps.