apex

noun

1. The highest or the greatest part of something, especially forming a point.
2. The highest point in a plane or solid figure, relative to a base line or plane.
3. The lowest part of the human heart.
4. The deepest part of a tooth's root.
5. The end of a leaf, petal or similar organ opposed to the end where it is attached to its support.
6. The growing point of a shoot.
7. The point on the celestial sphere toward which the Sun appears to move relative to nearby stars.
8. The lowest point on a pendant drop of a liquid.
9. The end or edge of a vein nearest the surface.
10. A diacritic in Classical Latin that resembles and gave rise to the acute.
11. A diacritic in Middle Vietnamese that indicates /ŋ͡m/.
12. 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".
13. The part of a corner where the racing line is nearest the inside of the bend.
14. A woman's crotch and sex organs.
15. An obstacle for a horse to jump over, consisting of a triangular corner fence.
16. The moment of greatest success, expansion, etc.
17. The top of the food chain.
18. A conical priest cap.