Head outside into a space where you have a clear view of the sky directly above your head and look up. The furthest visible point in the sky is the zenith. Dating back to the 1300’s, this interpretation of the word is the oldest and most wide-spread definition of “zenith”. Zenith refers to a point in the sky directly overhead a specific location in space. This point runs along an imaginary pole that extends vertically in the opposite direction of the gravitational force. If the celestial sphere is an assumed sphere with a radius of any arbitrary radius, then the zenith is the highest point in the celestial sphere from the perspective of the given reference. Having that said, zenith can also be used to describe the highest point in the orbit of a celestial body around a particular point of observation. The sun, for example, is at its zenith when it is directly overheard, i.e. mid-day.
The word zenith is derived out of error. From its origins in the Arabic expression `samt ar-ra’ (سمت الرأس), which means “way/path over the head”, the word was reduced to ‘samt’, which just means “direction.” During the Middle Ages in the 14th Century, the letter ‘m’ in the word ‘samt’ was misread as ‘ni’ by Medieval Latin scribes, turning the word into ‘senit’ or ‘cenit’. The word later evolved into the Old French word cenith, from which the modern English word ‘zenith’ was developed in the 17th century.
Over the years, the word has also developed a variety of other uses:
In science, the zenith is used as a reference point to measure the angle – namely the ‘zenith angle’ – between a direction of interest (like a celestial body or a UFO) and the zenith of the point of observation.
The word can also be used in its looser and less definitive form as a reference to the general expanse of sky overhead. Often, this use of the word also implies that the zenith is the highest or culminating point of the sky. If I wanted to exaggerate my strength, for example, I could say that I threw the ball all the way into the zenith. Unlike the first definition that was explored, this use of the word doesn’t specify a direction that lies directly above a given point. In essence, it is the same thing as the celestial sphere.
In its figurative sense – which is what we generally encounter in modern literature – zenith refers to the highest point or state and is synonymous with words like peak, climax, culmination and acme. The prime in a person’s life, for example, would be his or her zenith. The point at which a product is highest in demand would be its zenith. Stress-levels before a deadline are at their zenith, and so on.
- "Zenith." Home : Oxford English Dictionary. N.p., n.d. Web. 21 Nov. 2012. <http://www.oed.com/view/Entry/232785?redirectedFrom=zenith>.
- "Zenith." Merriam-Webster. Merriam-Webster, n.d. Web. 21 Nov. 2012. <http://www.merriam-webster.com/dictionary/zenith>.