An Apex

1. conical priest cap
2. The highest or the greatest point of something.
3. (figuratively) The moment of greatest success, expansion, etc.
4. (geometry) The topmost vertex of a cone or pyramid (in their conventional orientation).
5. (chiefly anatomy) The "pointed" fine end of something.

• The lowest part of the human heart.
• The deepest part of a tooth's root.

6. (botany) The end of a leaf, petal or similar organ opposed to the end where it is attached to its support; the tip.
7. (astronomy) The point on the celestial sphere toward which the sun appears to move relative to nearby stars.
8. (physics) The lowest point on a pendant drop of a liquid.
9. (mining, US) The end or edge of a vein nearest the surface.
10. (typography) A diacritic in Classical Latin that resembles and gave rise to the acute.
11. (typography) A diacritic in Middle Vietnamese that indicates /ŋ͡m/.
12. (typography) 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. (attributive, ecology) The top of the food chain

(highest point): peak, top, summit

(moment of greatest success, expansion, etc): acme, culmination, height, peak, pinnacle

(pointed end): end, tip