zenith n.

Proto-Indo-European root meaning "to change, go, move," "with derivatives referring to the exchange of goods and services within a society as regulated by custom or law" [Watkins].

It forms all or part of: amiss; amoeba; azimuth; common; commune; communicate; communication; communism; commute; congee; demean; emigrate; emigration; excommunicate; excommunication; immune; immutable; incommunicado; mad; mean (adj.1) "low-quality;" mew (n.2) "cage;" mews; migrate; migration; mis- (1) "bad, wrong;" mistake; Mithras; molt; Mstislav; municipal; munificent; mutable; mutant; mutate; mutation; mutatis mutandis; mutual; permeable; permeate; permutation; permute; remunerate; remuneration; transmutation; transmute; zenith.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit methati "changes, alternates, joins, meets;" Avestan mitho "perverted, false;" Hittite mutai- "be changed into;" Latin mutare "to change," meare "to go, pass," migrare "to move from one place to another," mutuus "done in exchange;" Old Church Slavonic mite "alternately;" Czech mijim "to go by, pass by," Polish mijać "avoid;" Gothic maidjan "to change."

"arc marking the distance of a star from the north or south point of the meridian," late 14c., from Old French azimut, from Arabic as-sumut "the ways," plural of as-samt "the way, direction" (see zenith). Related: Azimuthal.

late 14c., in astronomy, "imaginary point of the celestial sphere vertically opposite to the zenith of the sun; the inferior pole of the horizon," from Medieval Latin nadir, from Arabic nazir "opposite to," in nazir as-samt, literally "opposite direction," from nazir "opposite" + as-samt "road, path" (see zenith). Transferred sense of "lowest point" of anything is recorded by 1793.