EQUINOX

Pronunciation (US):

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 Dictionary entry overview: What does equinox mean? 

• EQUINOX (noun)
  The noun EQUINOX has 2 senses:

1. 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. (astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic

  Familiarity information: EQUINOX used as a noun is rare.

 Dictionary entry details 

• EQUINOX (noun)

Sense 1

Meaning:

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

Classified under:

Nouns denoting time and temporal relations

Hypernyms ("equinox" is a kind of...):

cosmic time (the time covered by the physical formation and development of the universe)

Hyponyms (each of the following is a kind of "equinox"):

March equinox; spring equinox; vernal equinox (March 21)

autumnal equinox; fall equinox; September equinox (September 22)

Derivation:

equinoctial (relating to an equinox (when the lengths of night and day are equal))

Sense 2

Meaning:

(astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic

Classified under:

Nouns denoting spatial position

Synonyms:

equinoctial point; equinox

Hypernyms ("equinox" is a kind of...):

celestial point (a point in the heavens (on the celestial sphere))

Domain category:

astronomy; uranology (the branch of physics that studies celestial bodies and the universe as a whole)

Hyponyms (each of the following is a kind of "equinox"):

vernal equinox ((astronomy) the equinoctial point that lies in the constellation of Pisces)

autumnal equinox ((astronomy) the equinoctial point that lies in the constellation of Virgo)

 Context examples 

The researchers examined data collected by Cassini's Composite Infrared Spectrometer during the year around equinox.

(At Saturn, One of These Rings is not like the Others, NASA)

Cassini's observations have shown a large-scale reversal of this system, beginning immediately after the equinox in 2009.

(Cassini Sees Dramatic Seasonal Changes on Titan, NASA)

In particular, around the equinox — the time when the Sun crosses Titan's equator — massive clouds can form in tropical regions and cause powerful methane storms.

(Dust Storms on Titan Spotted for the First Time, NASA)

The season between the autumnal equinox and the winter solstice.

(Autumn, NCI Thesaurus)

I think if we had had the disposal of events—if Mansfield Park had had the government of the winds just for a week or two, about the equinox, there would have been a difference.

(Mansfield Park, by Jane Austen)

Every fourth year, at the vernal equinox, there is a representative council of the whole nation, which meets in a plain about twenty miles from our house, and continues about five or six days.

(Gulliver's Travels into several remote nations of the world, by Jonathan Swift)

Either of two points on the celestial sphere where the celestial equator intersects the ecliptic; either of the two times each year when the sun crosses the equator, and day and night are of equal length (spring equinox, fall equinox).

(Equinox, NOAA Paleoclimate Glossary)

In a recent study, a team of Cassini scientists reported that one section of the rings appears to have been running a slight fever during equinox.

(At Saturn, One of These Rings is not like the Others, NASA)

Within months following the equinox, the vortex in the stratosphere over the south pole had become prominent, as had an atmospheric "hot spot" at high altitudes.

(Cassini Sees Dramatic Seasonal Changes on Titan, NASA)

The team's analysis suggested the best explanation for the A ring's equinox temperatures was for the ring to be composed largely of particles roughly 3 feet (1 meter) wide made of mostly solid ice, with only a thin coating of regolith.

(At Saturn, One of These Rings is not like the Others, NASA)