List of Abstract Nouns: a

1. acoustics
2. action
3. activity
4. acute angle An abstract concept of a geometric feature that is the angle formed by two lines is smaller than a right angle and is less than 90 degree.last updated 4/16/2015
   http://en.wikipedia.org/wiki/Angle#Types_of_angles last updated 4/16/2015
5. adulthood The concept of an age span of a person that is the age span after youth or the state of being an adult.last updated 2/27/2015
   http://en.wikipedia.org/wiki/Adult last updated 2/27/2015
6. aftermath
7. afternoon
8. afterthought
9. anger
10. apex An abstract concept of a zero dimensional geometric feature that is the highest point or top of something when considering in upright position.last updated 4/16/2015
    http://en.wikipedia.org/wiki/Apex_%28geometry%29 last updated 4/16/2015
11. arithmetic