Pupils can refer to:
1. The dark circular opening in the center of the iris of the eye, which contracts and expands to regulate the amount of light entering the eye.
2. A student in school, especially a child or young person who is being taught.
3. In law, a person under the age of puberty or under the care of a guardian.
Fun fact: The word "pupil" comes from the Latin word "pupilla", meaning "little doll", because when you look into someone's eyes, you can see a tiny reflection of yourself.