sphere vs zenith

sphere and zenith both are nouns.

Word	Noun	Adjective	Verb	Adverb
sphere	Yes	No	No	No
zenith	Yes	No	No	No

sphere (noun)	zenith (noun)
any spherically shaped artifact	the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected
a particular aspect of life or activity
the geographical area in which one nation is very influential
the apparent surface of the imaginary sphere on which celestial bodies appear to be projected
a solid figure bounded by a spherical surface (including the space it encloses)
a three-dimensional closed surface such that every point on the surface is equidistant from the center
a particular environment or walk of life