An intercalary year, also known as a leap year, is a year that has an extra day added to the calendar to keep it in sync with the Earth's orbit around the sun. Some synonyms for this term include "leap year," "bissextile year," and "embolismic year." The term "leap year" comes from the fact that the extra day "leaps over" a day in the regular calendar. "Bissextile year" is based on the ancient Roman practice of adding an extra day to February every four years. "Embolismic year" is a less commonly used term that originates from the Greek word "embolimos," meaning "intercalary." Regardless of the term used, intercalary years play an important role in keeping our calendars accurate and consistent with astronomical cycles.