What is Fraction ?
Fraction is (noun) 1. a very small amount Sales are up a fraction this month. Move the camera a fraction to the right, and you’ll all get in the picture. 2. (in mathematics) less than a whole number ¼ and ½ are fractions. 3. a small part of something Only a fraction of the stolen money was ever found.
source: Easier English, Student Dictionary Upper Intermediate Level