Gregorian calendarThe Gregorian calendar is the calendar used in most parts of the world. It went into effect in October 1582 following the papal bull Inter gravissimas issued by Pope Gregory XIII, which introduced it as a modification of, and replacement for, the Julian calendar. The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun.
KhalsaKhalsa (ਖ਼ਾਲਸਾ, ˈkhaːlsaː, to be pure) refers to both a community that considers Sikhism as its faith, as well as a special group of initiated Sikhs. The Khalsa tradition was initiated in 1699 by the Tenth Guru of Sikhism, Guru Gobind Singh. Its formation was a key event in the history of Sikhism. The founding of Khalsa is celebrated by Sikhs during the festival of Vaisakhi. Guru Gobind Singh started the Khalsa tradition after his father, Guru Tegh Bahadur, was beheaded during the Islamic sharia rule of the Mughal Emperor Aurangzeb.
MonthA month is a unit of time, used with calendars, that is approximately as long as a natural orbital period of the Moon; the words month and Moon are cognates. The traditional concept arose with the cycle of Moon phases; such lunar months ("lunations") are synodic months and last approximately 29.53 days, making for roughly 12.37 such months in one Earth year. From excavated tally sticks, researchers have deduced that people counted days in relation to the Moon's phases as early as the Paleolithic age.
Hindu calendarThe Hindu calendar, (also called Panchanga) (पञ्चाङ्ग) or Panjika is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start.
