Definition of "æquinox"

[T]he Months of March and September, the tvvo Æquinoxes of Our year, are the moſt vvindy and tempeſtuous, the moſt unſettled and unequable of Seaſons in moſt Countries of the VVorld.

1692 December 15, Richard Bentley, A Confutation of Atheism from the Origin and Frame of the World. The Third and Last Part. […], London: […] H[enry] Mortlock […], published 1693, pages 25–26

For [Julius] Cæsar says, that on the night of the fourth day after his landing there was a full moon. He had before mentioned that the summer was far spent, and the æquinox not come, hence, the full moon must have been either in July or August.

1854, John Williams, “Pro-consul. b.c. 55.”, in The Life of Julius Cæsar, London, New York, N.Y.: G[eorge] Routledge & Co., […], page 195