Orbital node

[6]: p.141,  [7]: p.245  These terms originally referred to the times when the Moon crossed the apparent path of the sun in the sky (as in a solar eclipse).

Also, corruptions of the Arabic term such as ganzaar, genzahar, geuzaar and zeuzahar were used in the medieval West to denote either of the nodes.

The gravitational pull of the Sun upon the Moon causes its nodes to gradually precess westward, completing a cycle in approximately 18.6 years.

[1][13] The image of the ascending and descending orbital nodes as the head and tail of a dragon, 180 degrees apart in the sky, goes back to the Chaldeans; it was used by the Zoroastrians, and then by Arabic astronomers and astrologers.

[14] Among the arguments against astrologers made by Ibn Qayyim al-Jawziyya (1292–1350), in his Miftah Dar al-SaCadah: "Why is it that you have given an influence to al-Ra's [the head] and al-Dhanab [the tail], which are two imaginary points [ascending and descending nodes]?