Meaning

noun the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected

originFrom Middle English cenyth, from Medieval Latin cenit, from Arabic سَمْت (samt, “direction, path”), from the fuller form سَمْت اَلرَّأْس (samt ar-raʔs, “direction of the head”). The -ni- for -m- is sometimes thought to be due to a misreading of the three strokes, which is plausible, though it could be a mere phonetic approximation.

Etymology from Wiktionary, CC BY-SA 3.0