In the USA, the final stage of mandatory education, encompassing either 9th through 12th grade, or 10th through 12th grade, depending on location, or the building in which this education takes place.
Like junior high, the day is broken into periods, between which students move from class to class. The classes in high school, listed in chronological order, are called: freshman, THPT (https://lambangcapgiarenhat.com/) sophomore, junior, senior.