Definition of "equinoctial" [e•qui•noc•tial]

• Relating to an equinox. (adjective)
• Relating to the celestial equator. (adjective)
• A violent storm of wind and rain occurring at or near the time of the equinox. (noun)
• See celestial equator. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The equator is the line C, D, which upon the globe is a circle, and is sometimes called the equinoctial: Upon this circle the degrees of longitude are reckoned, beginning at C, and counting all round the globe till you come to C again; and O is the middle of the world between A and B, which are the two poles thereof: A representing the"
• "As one half of the ecliptic is north, and the other half south, of the equator, the line of intersection of their planes is at two points which are known as the equinoctial points, because, when the Sun on his upward and downward journey arrives at either of them the days and nights are of equal length all over the world."
• "The two first stars named are exactly on what is called the equinoctial line."