Definition of equinoctial in English:

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Pronunciation: /ˌiːkwɪˈnɒkʃ(ə)l/
Pronunciation: /ˌɛkwɪˈnɒkʃ(ə)l/


1Happening at or near the time of an equinox: equinoctial gales
More example sentences
  • The nights start drawing in quite quickly, and by late September the first of the equinoctial gales will have appeared with the weather in the hills of Scotland turning decidedly chilly at times.
  • They are also equinoctial tides, occurring just after the autumn equinox on September 23, which would normally bring the highest tides of the year.
  • But Numa may also have had an equinoctial birthday.
1.1Having a day and night of equal length.
Example sentences
  • One of the effects of equinoctial periods is their temporary disruptive effect on communications satellites.
  • The sundial above, dated 1509, shows equinoctial hours with a gnomon parallel to the earth's axis.
1.2At or near the equator: the equinoctial region of the ocean
More example sentences
  • The Orinoco, the Eio Magdalena, and the Congo or Zaire, are the only great rivers of the equinoctial region of the globe.
  • Lindley has made us acquainted with a species of Salix belonging to Senegal, and therefore to the equinoctial region of Africa.


(also equinoctial line) another term for celestial equator.
Example sentences
  • A star on the north side of the equinoctial is in northern declination, and one on the southern side is in southern declination.
  • The declination of a heavenly body is its angular distance from the equinoctial or celestial equator.


Late Middle English (in the sense 'relating to equal periods of day and night'): via Old French from Latin aequinoctialis, from aequinoctium (see equinox).

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Line breaks: equi|noc¦tial

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