The definition of a nanny is a caretaker who takes care of a child, through the growing years. Nannies are mostly female and traditionally, the nanny was a servant of the house, who used to report directly to the lady of the house. With time, the role of nannies has transcended from an ordinary servant to the dominating presence in the child's life. Nannies in aristocratic families even have nursery maids working under them and are very respected. They are responsible for bringing up successive generations.

Though part-time babysitters are the current trend, a full- time nanny has her own position. A full-time nanny is an expensive investment because of her multi faceted role in the child's life. She does not just take care and support the development in the social, physical, emotional, intellectual and creative aptitudes of the child, but also takes care of the household. This includes maintaining the cleanliness of the house and regular communication with the parents regarding the child's development. She is expected to look after the child during the hours of service agreed upon in the terms and conditions. She is responsible for the child's safety, cooking nutritious meals and snacks and performing related tasks.

Women, between 20 to 30 years of age usually take up the job of a nanny, though, sometimes younger or older nannies are also considered. Previously, nannies wore uniforms.

Several nanny service agencies are available, who help parents to find the right nanny for their children. These organizations evaluate the nanny's educational and cultural background, her experience and love for children, safety awareness and personal character traits. The agencies offer credentials and rank the candidates through different tests. Childcare and guidance are instinctive qualities and there have been instances where nannies have become an integral part of the family.