apex vs vertex

apex and vertex both are nouns.

Word	Noun	Adjective	Verb	Adverb
apex	Yes	No	No	No
vertex	Yes	No	No	No

As nouns, apex and vertex are synonyms defined as:

Other synonyms of apex include acme, peak.

apex (noun)	vertex (noun)
the highest point (of something)	the point of intersection of lines or the point opposite the base of a figure
the point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars	the highest point (of something)