- The highest point of something, especially a mountain or roof.
- The highest or culminating point, especially of achievement or development.
Late 16th century: from latin apex "summit", originally "a point", from apere "be sharp".
- Mount Everest is the apex of the Himalayan mountain range.
- The apex of his career was when he won the Nobel Prize for Literature.
- The apex of the roof was just high enough for a tall person to stand up straight.
- The company's success was at its apex during the early 2000s.
- The apex of a triangle is the point at the top of the triangle, opposite the base.