a·pex 
(āpĕks)
(āpĕks)n. pl. a·pex·es or a·pi·ces (āpĭ-sēz′, ăpĭ-)
1.
a. The highest point of a structure, object, or geometric figure: the apex of a hill; the apex of a triangle.
b. The usually pointed end of an object; the tip: the apex of a leaf.
2.
a. The highest level or degree that is attained, as in a hierarchy. See Synonyms at summit.
b. The period of greatest achievement: won several Olympic medals at the apex of her career.
[Latin.]
- unevenly
- unevenness
- uneventful
- uneventfully
- unexampled
- unexceptionable
- unexceptionably
- unexceptional
- unexceptionally
- unexpected
- unexpectedly
- unexpectedness
- unexploited
- unexpressed
- unexpressive
- unexpressively
- unexpressiveness
- unfading
- unfadingly
- unfailing
- unfailingly
- unfair
- unfairly
- unfairness
- unfaith