Jalali

Jalali refers primarily to the Jalali calendar, a solar calendar used in Iran and parts of the surrounding region. Also called the Solar Hijri calendar, it is one of the most accurate solar calendars in use today and serves as the official civil calendar of Iran. The calendar was developed in the 11th century during the Seljuk period and is named after the Seljuk sultan Jalal ad-Din Malik Shah I, with significant contributions from astronomers such as Omar Khayyam. It reformed earlier Persian calendars and established Nowruz, the vernal equinox, as the start of each year.

The Jalali calendar comprises 12 months with fixed day counts: Farvardin, Ordibehesh t, Khordad, Tir, Mordad, Shahrivar, Mehr, Aban, Azar, Dey, Bahman, and Esfand. A leap day is added to Esfand in leap years, keeping the calendar aligned with the solar year. Its leap-year system is designed to maintain a very close approximation to the tropical year, resulting in a high degree of long-term accuracy compared with many other calendars. The system remains the basis for civil timekeeping in Iran and has influenced calendar-reckoning in neighboring regions.

Beyond its use as a calendar, Jalali is also a Persian surname and given name. It appears in various contexts within Persian-speaking communities, including individuals and place names. As a term, Jalali thus encompasses both a historic calendrical system and a personal name.