Definitions:

1. In astronomical context, refers to the point in the celestial sphere that is directly overhead an observer. NOUN
   • The sun reaches its zenith at noon.
2. The highest or most successful point in a situation, careeer, or condition. NOUN
   • At the zenith of her career, she was the most sought-after actress in the industry.
3. The time at which something is most powerful or successful. NOUN
   • Under Justinian, the Byzantine Empire reached its zenith of influence.

Synonyms:

• acme
• apex
• climax
• high point
• peak
• pinnacle
• summit

NearBy Words:

• zenithal