Ayah

'...Precious, you have smut on your nose,' she [Meenakshi] added to Aparna, half looking around to tell an imaginary ayah to wipe it off with a handkerchief. (p.12)

Ayah is a female domestic servant in India, usually a maid and a nanny.

References:

• Ayah on thefreedictionary.com
• Ayah on Wikipedia