Definition:Calendar/Jewish

Definition
The Jewish calendar is a calendar based on both the phases of the moon and on the orbital period of earth around the sun.

The whose period is based on $12$ full cycles of phases of the moon.

The basic Jewish year is $354$ or $355$ days of $12$ months, each alternately $29$ and $30$ days long.

When the error between the Jewish year and tropical year becomes approximately $30$ days, a $13$th month is inerted into the year.

Also known as
The Jewish calendar is also known as the Hebrew calendar.