Pupil (noun) has two common senses: the dark circular opening in the center of the eye through which light enters, and a student, especially a pupil of a school. In eye context it is pronounced with two syllables and a stressed first syllable in most varieties; in the school context it can be stressed on the first syllable as well, though some speakers reduce to a single syllable in rapid speech. Overall, it denotes a learner or student in educational settings, with eye anatomy usage being the primary semantic distinction in most conversations.
Full pronunciation guide
