A pupil is one Who is under the close supervision of a teacher,either Because of his youth or because of specialization In some branch of study.In England pupil is use to describe one In school,Which means up through public schools such as Eton or Harrow, or through the secondary schools,equivalent to American High schools.In America pupil is now usually restricted to one Who is In an elementary school.Those called pupils regardless of age because of their specialization In some brach of study are designated by the subject they are studying, as are pupilas,music pupils,etc.