'''අධික අවුරුද්දඅවුරුද්දක්''' යනු සාමාන්ය වසරකට වඩා වැඩිපුර එක් දිනයක් හෝ දින ගණනක් හෝ අඩංගුවන වර්ශයකිවර්ෂයකි.(or, in the case of [[lunisolar calendar]]s, an extra month) in order to keep the [[calendar year]] synchronised with the [[astronomical year|astronomical]] or [[seasonal year]]. For example, in the [[Gregorian calendar]], February in a leap year has 29 days instead of the usual 28 so the year lasts 366 days instead of the usual 365. Because seasons and astronomical events do not repeat in a [[whole number]] of days, a calendar that had the same number of days in each year would, over time, drift with respect to the event it was supposed to track. By occasionally inserting (or ''[[intercalation|intercalating]]'') an additional day or month into the year, the drift can be corrected. A year that is ''not'' a leap year is called a ''[[common year]]''.
