A classroom reserved for study WordNet 3.0 & Open English WordNet

Study hall, known as private study, SAS, structured study or free periods in the United Kingdom, is a term for a place to have a study time during the school day where students are assigned to study when they are not scheduled for an academic class. Wikipedia

a place and/or time during the school day where students are assigned to study when they are not scheduled for an academic class Wikidata

A class period, usually in boarding school or high school, where students are afforded the time for independent study and homework assignments, as part of the curriculum or after hours, the last notably as a punishment called detention. Wiktionary

Class period. Wiktionary (translation)