Women who teach in a school.
Schoolmistresses help children learn and are usually kind and smart.
Examples:
The schoolmistresses teach us how to read and write.
The schoolmistresses are very nice to us.
We listen to the schoolmistresses when they talk.
The schoolmistresses help us learn, but they don't give us too much homework.
All the children like the schoolmistresses because they are good at teaching.
The schoolmistresses know many things and they tell us about them.