1. Any of various systems of reckoning time in which the beginning, length, and divisions of a year are defined, sometimes along with multiyear cycles.
2. A table showing the months, weeks, and days in at least one specific year.
3. A schedule of events.
4. An ordered list of matters to be considered:the bills on a legislative calendar.
5. Chiefly British A catalog of a university.
tr.v. cal·en·dared, cal·en·dar·ing, cal·en·dars
To enter in a calendar; schedule.
[Middle English calender, from Old French calendier, from Late Latin kalendārium, from Latin, account book, from kalendae, calends (from the fact that monthly interest was due on the calends); see kelə-2 in the Appendix of Indo-European roots.]
THREE PRINCIPAL CALENDARS
The Gregorian calendar is now in use as the civil calendar throughout most of the world. The Jewish calendar is the official calendar of the Jewish religious community. The Islamic calendar is the official calendar in many Muslim countries. Each calendar listed below begins with the first month of the year and includes the number of days each month contains. Many months have a variable number of days, as described below.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.