What does tutor mean?

As a noun it means a private teacher working with one student or a small group. As a verb it means to teach that way. It comes from the Latin ‘tutor’, meaning a guardian or watcher — someone responsible for one person rather than for a class of thirty. That origin is closer to the real job than modern usage suggests: most of what this work consists of is noticing what one particular child is doing, which nobody can do for thirty at once.