Also found in: Thesaurus, Legal, Encyclopedia.
1. One of two points at which the ecliptic intersects the celestial equator. At the autumnal equinox, the sun is moving along the ecliptic in a southeasterly direction.
2. The moment at which the sun passes through this point on or about September 23, marking the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Physical Geography) the time at which the sun crosses the plane of the equator away from the relevant hemisphere, making day and night of equal length. It occurs about Sept 23 in the N hemisphere (March 21 in the S hemisphere)
2. (Astronomy) the time at which the sun crosses the plane of the equator away from the relevant hemisphere, making day and night of equal length. It occurs about Sept 23 in the N hemisphere (March 21 in the S hemisphere)
3. (Astronomy) astronomy
a. the point, lying in the constellation Virgo, at which the sun's ecliptic intersects the celestial equator
b. the time at which this occurs as the sun travels north to south (23 September)
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
1. See under equinox (def. 1).
2. Also called autum′nal point′. the position of the sun at the time of the autumnal equinox.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
The moment of the year when the sun crosses the celestial equator while moving from north to south. It occurs on September 22 or 23, marking the beginning of autumn in the Northern Hemisphere. Compare vernal equinox.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Switch to new thesaurus
|Noun||1.||autumnal equinox - September 22 |
equinox - either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length
|2.||autumnal equinox - (astronomy) the equinoctial point that lies in the constellation of Virgo|
astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.