Zenith refers to the strongest or most successful period of time for a person or thing.
When you reach the zenith, you're at the top, the pinnacle, the summit, the peak.
Zenith developed from an Arabic phrase meaning "the way over one's head," and then traveled through Old Spanish, Medieval Latin, and Middle French before arriving in English.
Figuratively, nadir simply means "the lowest point."
Optimized studying based on the forgetting curve vastly improves memorization. - What is reminDO?
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