noun Date: 1766 fifteen minutes, any of the quarter points of an hour, a unit of academic credit representing an hour of class (as lecture class) or three hours of laboratory work each week for an academic quarter
QUARTER HOUR
Meaning of QUARTER HOUR in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012