Syzygy
Etymology
From Greek "syzygia" ("union, a pairing, a yoking"), via "syzygos" ("yoked together"), from "syn-" ("together") plus "zygon" ("yoke"). Astronomy narrowed it to the alignment of three bodies; the word keeps its old flavor of things bound into a single configuration.
noun · /SIZ-ih-jee/
A straight-line alignment of three celestial bodies, such as the Sun, Earth, and Moon during an eclipse.
What it names
A rare and beautiful word for the moment separate things fall into perfect alignment — literally in the sky, or figuratively when circumstances line up.
Example
The launch, the funding, and the perfect team arriving at once felt like a business syzygy that would never recur.
Related idea
A conjunction is just two bodies appearing close together; a syzygy is the stricter, three-body straight-line arrangement that actually produces eclipses and tides.