/ ˈzenɪθ; NAmE / noun
1.
the highest point that the sun or moon reaches in the sky, directly above you
2.
( formal ) the time when sth is strongest and most successful
SYN peak
OPP nadir
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WORD ORIGIN
late Middle English : from Old French or medieval Latin cenit , based on Arabic samt (ar-ra's) path (over the head).