Calendar is a system by wich time is divided into fixed period, showing the begining and end of a year (Oxford Dictionary). Usually a calendar represent by chart showing days, weeks and months of a particular year. Day is a term for the average time required for one rotation of the earth. In other word, a day is a time from the morning time to the next morning time.
There is two major system to measuring year. The first system is the solar calendar. The solar calendar using the earth revolution cycling the sun as the refference. It means that one year at the solar calendar is the time takes by the earth to complete cycling the sun. A year, in Solar calendar contains approximately 365,25 days.
The second calendar system is the lunar calendar. The lunar calendar using the moon revolution cycling the earth as the refference. It means that one year at the lunar calendar is the time takes by the moon to complete cycling the earth. A year in Lunar Calendar contains 354 days.
Both lunar and solar calendar are used to measuring and remembering days for several purpose. The difference is that the solar calendar is more popular than the lunar calendar. But that doesn’t mean that the lunar calendar is no more used. The lunar calendar used by several religion to calculate the time of their holidays. Hindu, Islam, and Jew are using the moon revolution period as a refference for their calendar system .
