|Origin:||pinacle, from Late Latin pinnaculum, from Latin pinna 'wing, wall around the top of a castle'|
the most successful, powerful, exciting etc part of something:
the pinnacle of academic achievement
at the pinnacle of something
The bank was then at the pinnacle of England's financial system.
2 [countable] literaryDN
a high mountain top
a pointed stone decoration, like a small tower, on a building such as a church or castle