apex vs pinnacle

apex

noun
  • The highest or the greatest part of something, especially forming a point. 

  • The top of the food chain. 

  • The moment of greatest success, expansion, etc. 

  • The end or edge of a vein nearest the surface. 

  • A conical priest cap. 

  • The highest point in a plane or solid figure, relative to a base line or plane. 

  • The end of a leaf, petal or similar organ opposed to the end where it is attached to its support. 

  • The growing point of a shoot. 

  • The deepest part of a tooth's root. 

  • A diacritic in Middle Vietnamese that indicates /ŋ͡m/. 

  • A diacritic in Classical Latin that resembles and gave rise to the acute. 

  • The lowest part of the human heart. 

  • The point on the celestial sphere toward which the Sun appears to move relative to nearby stars. 

  • A sharp upward point formed by two strokes that meet at an acute angle, as in "W", uppercase "A", and closed-top "4", or by a tapered stroke, as in lowercase "t". 

  • The lowest point on a pendant drop of a liquid. 

pinnacle

noun
  • The highest point. 

  • An upright member, generally ending in a small spire, used to finish a buttress, to constitute a part in a proportion, as where pinnacles flank a gable or spire. 

  • Coordinate term: sea stack 

  • A tall, sharp and craggy rock or mountain. 

  • An all-time high; a point of greatest achievement or success. 

verb
  • To place on a pinnacle. 

  • To build or furnish with a pinnacle or pinnacles. 

How often have the words apex and pinnacle occurred in a corpus of books? (source: Google Ngram Viewer )