A dormitory is a building at a boarding school, college, or university where students live. Many students have roommates in a dormitory, and sometimes those roommates put up really cheesy posters of shirtless guys leaning on cars.
The word dormitory is from the Latin dormitorium for "sleeping place," and if you keep going back you get to dormire for "to sleep." A dormitory is where students who live at school sleep — well, it’s where their beds are anyway. Often the first time kids sleep away at school is when they go to college. There are often different dorms for freshman and older students. Dormitories are also called dorms, residence halls, and student residences.