From Longman Dictionary of Contemporary Englishstudy hallˈstudy hall noun [uncountable] American EnglishSE a period of time during the school day when students must go to a room to study, instead of going to a lesson
Examples from the Corpus
study hall• The class worked much like a study hall, but with just a few students helped by one teacher.• We had fourteen check-ins a day, classes in Latin, a vigorous program of athletics and every night a study hall.• Too many seniors are floating through their final year in high school in a combination of elective classes and study hall.• With parental approval all the students elected to meet with the counselor in lieu of another subject or study hall. 