Yes, apex is a Scrabble word!
...and is worth 13 points in Scrabble, and 14 points in Words with Friends
apex
Noun
1. The highest point (of something)
2. The point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars
What Scrabble words can I make with the letters in apex?
3 Letter Words
2 Letter Words