A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. The word “calendar” comes from the Latin word “calends,” which referred to the first day of the month in the Roman calendar. Calendars are used to keep track of time, plan events, and commemorate important dates.
The Gregorian calendar is the most widely used calendar in the world today. It was introduced by Pope Gregory XIII in 1582 and is based on the solar year, which is the time it takes for the Earth to orbit the sun. The Gregorian calendar has 12 months, with 28 days in February in a common year and 29 days in February in a leap year.
