/ ˈpɪnəkl; NAmE / noun
1.
[ usually sing. ] pinnacle of sth the most important or successful part of sth :
the pinnacle of her career
2.
a small pointed stone decoration built on the roof of a building
3.
a high pointed piece of rock, especially at the top of a mountain
••
WORD ORIGIN
Middle English : from Old French , from late Latin pinnaculum , diminutive of pinna wing, point.