zenith Definition

zenith
noun

1. astron.
The point on the celestial sphere diametrically opposite the nadir and directly above the observer. Also called vertex.
2. The highest point.

Thesaurus: top, summit, pinnacle, peak, apex, apogee, climax, acme, vertex; Antonym: base, bottom, nadir.

Etymology: 14c as cinit or cenith, etc: ultimately from Arabic samt-ar-ras direction of the head.