A calendar is a system of organizing days for social, religious, commercial or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single, specific day within such a system. The term calendar is taken from calendae , the term for the first day of the month in the Roman calendar, related to the verb calare , referring to the "calling" of the new moon when it was first seen. The Latin term was adopted in Old French as calendier and from there in English as calender by the 13th century. Sikh Nanakshahi Calendar Indian Calendar The Bikrami calendar has been historically used by Hindus and Sikhs. The Bikrami or Vikrami calendar is named after king Vikramaditya and starts in 57 B.C. It is based on twelve syndicalist lunar months and 365 solar days. The lunar new year starts on the new moon in the month of Chet. Lunar Calendar - 2018 In Bikrami Calendar, a lunar month has two