A (dated) term for a female childcare worker or nursery school teacher. Nowadays the term 保育士 (hoikushi) is commonly used.
昔は保母と呼ばれていたが、今は保育士ということが多い。
In the past they were called 'hobo', but now they are often called 'hoikushi' (childcare workers).
保母は子どもの食事や遊びの世話をする仕事だ。
A childcare worker takes care of children's meals and play.