A LEAP year is a kind of year that occurs every four years, adding an extra day to the calendar. An ACADEMIC year is a kind of year that typically runs from September to June and is used by educational institutions. A SOLAR year is a kind of year that is based on the time it takes for the Earth to orbit the Sun, which is approximately 365 days. A FISCAL year is a kind of year that is used by businesses and governments for accounting purposes and may not necessarily coincide with the calendar year. Finally, a lunar year is a kind of year that is based on the phases of the Moon, which is approximately 354 days.