Definition of equinoctial in English:



  • 1Happening at or near the time of an equinox.

    ‘equinoctial gales’
    • ‘You know, it's s good thing you're coming at the beginning of the month - that way you won't feel the force of the equinoctial storms’
    • ‘They are also equinoctial tides, occurring just after the autumn equinox on September 23, which would normally bring the highest tides of the year.’
    • ‘That's the simple explanation anyway - you can check the exact equinoctial dates and times here, if you're so inclined.’
    • ‘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.’
    • ‘Outside, the equinoctial storms of mid-September are raging.’
    • ‘Two large stones also stand almost due east and west to mark the local equinoctial positions of the sun.’
    • ‘But Numa may also have had an equinoctial birthday.’
    1. 1.1 Having a day and night of equal length.
      • ‘The sundial above, dated 1509, shows equinoctial hours with a gnomon parallel to the earth's axis.’
      • ‘One of the effects of equinoctial periods is their temporary disruptive effect on communications satellites.’
    2. 1.2 At or near the equator.
      ‘the equinoctial region of the ocean’
      • ‘Lindley has made us acquainted with a species of Salix belonging to Senegal, and therefore to the equinoctial region of Africa.’
      • ‘The Orinoco, the Eio Magdalena, and the Congo or Zaire, are the only great rivers of the equinoctial region of the globe.’


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


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