A tutor is an instructor who gives private lessons. the most famous example of a tutor is aristotle, who tutored alexander the great. a tutor is not to be confused with a teacher who is employed in the education of groups. to tutor (as a verb) is to perform the functions of a tutor. shadow education is a pejorative name for private supplementary tutoring that is offered outside the mainstream education system. private tutoring can help high achievers reach new levels.