[ ee-kwuh-nok-shuh l, ek-wuh- ]
/ ˌi kwəˈnɒk ʃəl, ˌɛk wə- /


pertaining to an equinox or the equinoxes, or to the equality of day and night.
pertaining to the celestial equator.
occurring at or about the time of an equinox.
Botany. (of a flower) opening regularly at a certain hour.


Origin of equinoctial

1350–1400; Middle English < Latin aequinoctiālis pertaining to the equinox. See equinox, -al1

OTHER WORDS FROM equinoctial

in·ter·e·qui·noc·tial, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for equinoctial

British Dictionary definitions for equinoctial

/ (ˌiːkwɪˈnɒkʃəl) /


relating to or occurring at either or both equinoxes
(of a plant) having flowers that open and close at specific regular times
astronomy of or relating to the celestial equator


a storm or gale at or near an equinox
another name for celestial equator

Word Origin for equinoctial

C14: from Latin aequinoctiālis concerning the equinox
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for equinoctial

[ ē′kwə-nŏkshəl, ĕk′wə- ]


Relating to an equinox.
Relating to the celestial equator.


See celestial equator.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.