A calendar that measures the passage of the year according to the phases of the moon, as opposed to the revolution of the earth around the sun; a calendar of the lunar year.

A calendar used to count down the days of Advent, having windows revealing a hidden picture or gift on each day.

The period of duration from the first date of one month to the last date of the same month, which can thus vary from 28 to 31 days in length.

(finance) An options strategy or position involving the simultaneous purchase and sale of options of the same class and strike price but with different expiration dates.

The amount of time between the beginning of the first day of January and the end of the last day of December in the Gregorian calendar. (365 days, or 366 in a leap year)

A rhythm method of natural birth control.

plural of Advent calendar

A calendar system associated with Islamic culture, dividing the year into twelve months.

plural of calendar month

plural of calendar year