A gymnasium is a type of school in some countries, mostly in Europe. It's like your school, but for older kids who are around 15-19 years old. You might compare it to high school or secondary school, but gymnasiums usually have a focus on academic subjects like languages, math, history, and science.
In a gymnasium, students usually study for three or four years before they graduate. During that time, they take many different classes in different subjects. They might learn about ancient civilizations, biology, literature, and much more. They might also have the opportunity to learn new languages like French or Spanish.
One thing that's different about gymnasiums is that they don't usually have many extracurricular activities like sports teams, music clubs, or drama productions. Instead, students focus on their academic work and might take part in study groups, debating societies, or other clubs that relate to their school subjects.
Overall, gymnasium can be a challenging but rewarding experience for students who want to pursue their education further and prepare for university.