The zenith (UK /ˈzɛnɪθ/, US /ˈziːnɪθ/) is an imaginary point directly "above" a particular location, on the imaginary celestial sphere. "Above" means in the vertical direction opposite to the apparent gravitational force at that location. The opposite direction, i.e. the direction in which gravity pulls, is toward the nadir. The zenith is the "highest" point on the celestial sphere (meaning it is the farthest up from the gravitational force).
Zenith is sometimes used as a given name, most commonly for males.