Syzygy

Either of two points in the orbit of a solar system body where the body is in opposition to or in conjunction with the sun.
Either of two points in the orbit of the moon when the moon lies in a straight line with the sun and Earth.
The configuration of the sun, the moon, and Earth lying in a straight line.

in philosophy: Syzygy, female–male pairings of the emanations known as Aeon (Gnosticism)